I've Been Killing Slimes for 300 Years and Maxed Out My Level is a tV series anime that premiered in spring 2021, produced by REVOROOT.

About the production: the story comes from a light novel, there are 12 episodes of about 24 minutes and its current status is "finished".

Its main genres are adventure, comedy, fantasy and slice of life, with themes such as Primarily Female Cast, Female Protagonist, Found Family and Family Life.

On AniList, I've Been Killing Slimes for 300 Years and Maxed Out My Level has an average score of 68%, a good score, and appears on 142,270 users' lists.

The franchise continues in or follows from: Slime Taoshite 300-nen, Shiranai Uchi ni Level MAX ni Nattemashita: Sono ni.

An at-home comedy about a powerful girl who doesn’t work too hard!(⋈◍ ˃ᴗ˂ ◍)。✧♡ After dying of overwork in the real world, I’m reincarnated as an immortal witch, and I spend 300 years enjoying a relaxing life. At some point, though, I end up at level 99! All those years spent killing slimes to make the money to pay the bills gave me a ton of experience points… Rumors of the level 99 witch spread, and soon I’m up to my ears in curious adventurers, duelist dragons, and even a monster girl calling me her mom! “This isn’t a dojo, so don’t come here to fight me…!” I’ve never been on an adventure, but I’m the strongest in the world… What’s going to happen to my relaxing life?! (Source: Crunchyroll)

Official synopsis from AniList.