I see you have posted  almost identically  elsewhere hoping to catch something from two ponds

Does every shape and size include Ubers? 

Here is an idea for you to try, give up and try to get something else, then go back to what you really want.

 Want a better idea?

Try the lairs.

Try L7 resource tiles.

It seems that you are waiting for one piece  of any class to enable you to get the last legendary piece  needed. 

Though I am not advocating otherwise,I am curious as to why you are waiting  for legendary, rather than settling for epic,

Yes, some guides might tell you anything below unusual is a waste of material, and preferably to only build legendary, but it seems most players ignore this and forge lower quality and then  upgrade.

Is it really better forge 2 to 5 lower quality items for a larger total % than the actual % of  just one or two pieces of higher quality like epic or legendary?

What gains are made by forging low, rather than loosing these by waiting till one can forge high? 

There must be some formula, though its probably complicated  to work out  the break even point. 

I am asking this because I am much further behind than you are in the collecting of invader materials.

The other choice is gamble with the forging odds, not doing so is easier understand.

It  must be frustrating waiting for the one piece you want and to start wondering about the randomness in the game.

We do not even know if the game uses fair randomness.

I have suspicions that the drops of basic materials from the  tasks isn't random at all, and perhaps it isn't meant to be,though I do not have the skills or mathematical knowledge to check this.

Response to ANYONE - Yes, I posted in two places cuz I wasn't sure if this would be categorized as a question or a request. Not trying to demand extra attention, just saw enough "This post has been moved to..." comments on others that I figured it'd be easier to just delete whichever one turned out to be in the wrong place. ;) To answer your other question... YES, "all shapes and sizes" does include the corresponding Ubers and their lairs.

Response to XYZ - Honestly, it just feels like giving up to have five matching gold pieces and then settling for a purple one after all this effort. The last step between epic and legendary shows the greatest stat improvement between classes as well so I'd be selling myself short to have come so close and not finished the set. . . All that, plus I'm a little OCD and I want my stuff to match. XP  I agree with you that the drops are likely not random.. in fact, I'd be hard to convince they weren't controlled by some sadistic formula with the purpose of making sure that the cost of getting what you want in this game will far outweigh the benefits of actually having it. From the sound of it, you and I would both benefit from any information on how to increase certain odds if any such method exists. If it does, the time and hero energy involved in figuring it out by oneself would probably be ten times the cost of the current method-mowing down Invaders with fingers crossed. 

Well you are fortunate in your ability to be able to hit Level 6 and more fortunate if you get good stuff  from the special event Ubers.

I suspect you  have to get L5 chests and to do that   probably means you also have to be able to hit  level 6.

I am lucky if I get level 4 chest, and I cant work out why and how, because sometimes the energy taken for a 3 is more than a 4, and vice versa

Adorsher. 

Thanks for the update. .

Did you get the last piece yet? 

I think it would be good if we could use common materials to craft uncommon ones.

For instance, 100 leather could be swapped for 1 leather straps, equivalent level, ie rare

Eleria**. 

Thanks for the update. .

Did you get the last piece yet? 

 I did manage to figure out one tidbit that I wish I'd realized sooner. A significant sustained attack bonus on a high level invader is the most cost efficient way to gain crafting materials, but don't just aim for the maximum. There may not be an exact formula, but I think I got the general idea ....

As your sustained attack grows, the quality of your rewards will fluctuate in a kind of "5 steps forward, 4 steps back" (or similar) pattern. This creates 'sweet spots' for your finishing blow. It's easy to figure out though. Watch your rewards closely as you kill invaders to see where your sustained attack is when it always gives you rare or epic material and then finish with an enhanced attack at one of those points, allowing for change as you gain different hunting bonuses. 

I hope this helps someone else before, like me, they waste their hero energy using all the wrong methods until they finally give up on the game entirely because not everyone has unlimited funds to spend on trial and error or blindly grinding away hoping for the best. 

I continue to increase my sustained attack until it has reached maximum ... and then I will a lot of times just keep hitting the invader with single attacks if I think it won't be "stolen" ... I like to see what I get from each hit. 

CIM said:

I continue to increase my sustained attack until it has reached maximum ... and then I will a lot of times just keep hitting the invader with single attacks if I think it won't be "stolen" ... I like to see what I get from each hit. 

Also I have over 50 pieces of equipment at legendary level that use invader material (invader or special or shaman equipment) ... this includes numerous "sets" of equipment.  That last piece you need for that last equipment to finish off a set is the most difficult ... that is why it is the last thing you need.  That being said the piece that is most difficult for you might be different than the piece most difficult for someone else.  My chief and I often are trying to make the same set at the same time and what he ends up needing at the end can be different than what I end up needing. 

Thank you CIM. I understand how it would seem logical to just go for a maxed out sustained attack, and perhaps with your exact effectiveness against Invaders, that happens to work out for you, but I've repeatedly seen the kill loot drop in quality if that final hit was delivered outside the last identifiable "peak" (when normal hits give epic or rare loot). I am sure you've been playing longer than me and I value your input on many topics, but from what I know of your journey in this game, it seems you haven't faced the same barriers as I have, specifically with maintaining hero energy. That said, since I believe you do have the means, please try my method out and keep track of the loot for a few Invaders before you knock it... I've just finished killing another 20 level 6s my way, then 5 with Max sustained attack, and 5 with single hits all the way to triple check my theory and it's still holding up, it doesn't even seem to matter which account I use. I'm just saying..It's possible you'll be surprised, and wouldn't it be nice if we could both confirm a method other than hit and pray?

CIM said:

I continue to increase my sustained attack until it has reached maximum ... and then I will a lot of times just keep hitting the invader with single attacks if I think it won't be "stolen" ... I like to see what I get from each hit. 

Also I have over 50 pieces of equipment at legendary level that use invader material (invader or special or shaman equipment) ... this includes numerous "sets" of equipment.  That last piece you need for that last equipment to finish off a set is the most difficult ... that is why it is the last thing you need.  That being said the piece that is most difficult for you might be different than the piece most difficult for someone else.  My chief and I often are trying to make the same set at the same time and what he ends up needing at the end can be different than what I end up needing. 

Thank you CIM. I understand how it would seem logical to just go for a maxed out sustained attack, and perhaps with your exact effectiveness against Invaders, that happens to work out for you, but I've repeatedly seen the kill loot drop in quality if that final hit was delivered outside the last identifiable "peak" (when normal hits give epic or rare loot). I am sure you've been playing longer than me and I value your input on many topics, but from what I know of your journey in this game, it seems you haven't faced the same barriers as I have, specifically with maintaining hero energy. That said, since I believe you do have the means, please try my method out and keep track of the loot for a few Invaders before you knock it... I've just finished killing another 20 level 6s my way, then 5 with Max sustained attack, and 5 with single hits all the way to triple check my theory and it's still holding up, it doesn't even seem to matter which account I use. I'm just saying..It's possible you'll be surprised, and wouldn't it be nice if we could both confirm a method other than hit and pray?

CIM... Do you mean other than my gel pen color coded notebook scribbles? :/ Cuz umm... My "data" is just page after page of basically copying the same info that's in the battle reports followed by some predictions based on patterns I saw.. it's not very technical. My predictions being accurate is what gave me the confidence to post my theory on here. Being a theory, I admit that it may have holes, the most obvious being that it could just be the product of coincidence. 

I don't know enough yet to create a formula, and if/when I do, it will likely be based on probability (of receiving higher grade material overall) more than certainty since I don't have access to the same information as someone who actually developed the game as nice as that would be. That's why I was kinda hoping someone...you, maybe ;).. would assist me a bit with a second pair of eyes, so to speak. Just... keeping track for a few Invaders that you finish in those different ways (without an offense boost cuz that seems to throw everything off, FTR) If you are intrigued at all, message me and I'll explain my "process" with more detail. If you think this idea was complete bunk before it hit the page and was concocted from desperation and delusion, then let me down easy and I'll drop it. (ಥ﹏ಥ)

This is very interesting and strangely familiar.......

Theories and pages of history of battle reports and trying to work a scheme.

The one fly in the ointment of this kind research is that we do not know when and if things change. 

The game is in a state of flux at best of times, rather than static, which means results can be meaningless.

I had also noticed what I thought appeared to be trends .

I would also agree with you that  the 20 % reduction or 10% now perhaps, isnt always beneficial to use when you talk about efficient use of energy.

Other ideas  on these lines that I wanted to test never happened,and updates have changed test conditions and likely worthiness.

Critcal hits  and high levels of sustained attack are supposed to help, but they appear to effect number of items dropping adversely at least at my level.

One thing I would  say definately changed .

I remember a time months ago now, when I thought I had encountered a glitch.

A non simple item   dropped from a level 1 invader, lately these are quite frequent, which would suggest something was tweaked.