We've done this a few time before and it's usually good fun.

Give me two lines of pokemon to fuse together, and be specific about individual fusions. i.e. don't just give me something like "paras line x blastoise line;" specify if it's
>paras/squirtle, paras/wartortle, parasect/blastoise
>paras/squirtle, parasect/wartortle, parasect/blastoise
or just
>paras/squirtle, parasect/blastoise

Specify similarly with split evos. Again, stick to fusing whole lines; Don't get convoluted and try and give me 7 different unrelated pokemon to fuse with the eeveelutions or something. Closely related pokemon like legendaries or obvious paired designs (like illumise and volbeat, or minun and plusle, etc...) are exceptions to that.

And most importantly, once a line has been fused (even if part of a line went unused) it's off the table and we keep going only with what's left over.

Hopefully some kindly drawfriends will grace us with some fun doodles.