As you grow stronger/higher level you will be able to get more. Example: I have 14 I can summon atm. Can get them all but need sooooooo many of those Soul Shards to get the rest and or more Gold than I can afford right now. Patience young grasshopper, they will come.

I'm assuming you mean the individual Aesir. Your thread title is a little vague/misleading. Good luck with the game and have fun :D

Then it should show the max number of Aesir you can have at any level on the Valley. This way you don't just pick the easy ones thinking there isn't a limit to what you can have. Also i upgraded Valley from 18-26 with no change to the number i can have, so having to get palace to level 32+ or so shouldn't be the fix for this lack of information.

You have misunderstood the limits on summoning Aesir.

If it is your Palace that you upgraded you now need to upgrade your Sanctuary of the Aesir - it is that building which determines the aesir which you can summon, as explained in the Info box for that building in game and in the Guide

https://support-portal.plarium.com/en/vikings-web/faq/aesir

A level 26 Palace allows you to upgrade the Sanctuary of the Aesir building to level 21 and that is sufficient to summon all of the 18 currently available Aesir.  To max out some of the Aesir requires a level 30 Sanctuary but it is somewhat unlikely that you will find that to be a very significant constraint.

In case it is helpful, it can be a mistake to prioritise your Palace (and the other buildings).  Knowledge tends to be more significant in aiding faster progress.