I loved overlord. I Watched it all at least 3 times. If you liked overlord I have a few suggestions for similar anime, Overlord is in my top 10 anime and these suggestions of mine are also in my top 10.
All time Favorite -
That time I got reincarnated as a slime -
Watch That Time I Got Reincarnated as a Slime Online
Summary: "Rimuru Tempest" is the new name of a slime in a fantasy world taken by a former 37-year-old human Satoru Mikami after he is killed by a passing robber. Broken free from ordinary, stale past life, his fresh adventure in a fantasy world as a slime monster with unique abilities begins.
How not to summon a demon lord -
Watch How Not to Summon a Demon Lord Online
Summary: In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist "I am the real summon master." Takuma gets slave-turning magic used for summoned beasts cast on him by the girls― However, the peculiar ability "Magic Reflection" is invoked! The ones that were turned to slaves were the girls! Takuma was bewildered. He's the strongest magician but, he doesn't have any social skills. Panicking, the first words that came out were the ones that he used inside the game role-playing the Demon King?! "I'm amazing you say? Of course I am. I am Diablo... The one feared as the Demon King!" This is the story the Demon King (acting) that would soon inspire the world and his other world adventure that he plunges through with his absolute strength, raise the curtain!
Death March to the Parallel World Rhapsody -
Watch Death March to the Parallel World Rhapsody Online
Summary: 29-year-old programmer Suzuki Ichirou finds himself transported into a fantasy RPG. Within the game, he's a 15-year-old named Satou. At first he thinks he's dreaming, but his experiences seem very real. Due to a powerful ability he possesses with limited use, he ends up wiping out an army of lizard men and becomes a high leveled adventurer. Satou decides to hide his level, and plans to live peacefully and meet new people. However, developments in the game's story, such as the return of a demon king, may cause a nuisance to Satou's plans.