Minecraft single monsters spawning on Peaceful?

I need a sleim on my map but otherwise I don't want any more monster zombies etc. To run around. Is there a solution with commands or something?

With / summon minecraft: daswasduebenwillst

simply add a tab.

if it should have certain values like no gravity or something, look on the website mcstacker / summon there you can set a lot and then copy out the command

Hmm, you can generally deactivate the natural spawning of monsters with / gamerule doMobSpawning false.