Skyblock Tech – If you want a specific special slime, you can just reroll it. This is the SAME slime:

Cage a special slime and toss it at least 10 silver coins, so it does not despawn.

You can now either teleport (or run/fly) more than 90 blocks aways. (outside of NPC spawning range)

When you return the slime will reroll its "special" atribute – in between being a normal one, holding items like coins or ore, holding blocks (wood/stone/dirt) or even becoming a Herb Slime if you're in the jungle.

Herb Slimes can usually only plant 5 herbs but it can spawn an infinite number of herbs this way, if you reroll it every 5 herbs. This method works great the more slimes you catch.