without buying them from the auction house

mine them with silk touch

cave spider spawners can be found in mineshafts, mine them with silk touch

Zombie, sheep, cow, skeleton, enderman, creeper, and iron golem can be found in /warp crates (vote keys needed from /vote or alternative methods) 

I think pillager spawners are found in pillager outposts.

The rest I don't really know

You can also buy them off of /ah with you money which can be earned by selling items on the /ah or /shop