Altan or deliana but hard to say since we dont know who you have at 60 yet ! 

i have kael at 60 so far 

Can you post a screenshot of your champions , either on phone using the capture screen function or on pc using the shift+window key+s ? Would look something like this ...

i

But also wait for the answes of forum people like Kram , Tripps , Harlequiin , Dthorne , etc , they give super useful advice , wouldnt be this far in the game without them !

I would go Deliana next. Easy to gear, brings some sustain to your team with her leech and A3 heal, and her passive. 

If you just have Kael at 60, Deliana is the way to go. Is amazing in early game, and lasts through at least endgame in solid Brutal+ Hydra teams. 

After that, we are likely looking at Altan, an amazing defense based damage dealer, with huge upside, and absolute bruiser in Clan Boss, which is your best source of free resources daily as you progress in difficulty.

sure heres mine

i