Similar games like this?

[Sanya]

I loved monster sanctuary and got 100% achievements so sadly i have nothing else to do here. Would love to see another dlc.

So are there any similar games to this?

[Conan The Librarian]

Sanya,

Glad you enjoyed things!

No more major updates are planned for Monster Sanctuary as we're focusing on our next game, Aethermancer.

In terms of "games similar to this", there aren't really any I can think of that are "directly similar". If you give parameters on what "kind" of game you seek, I can perhaps give some info on that.

[PKblaze]

I can't think of any monster catching metroidvanias but if you're wanting a good creature collector I cannot recommend Coromon enough. As a simiar kind of metroidvania, Indivisible has a similar game structure and games like Hollow Knight, Guacamelee, Dust an Elysian Tale etc are all great metroidvanias.

[Arxie]

Try Coromon- it's in the same genre sphere.

[Hatter]

Casette beasts is metrovania-like and is a monster collector.

[Worgen Freeman]

Its not a side scroller but it does play somewhat similar, turn based battles, and a lot of monster personality, you can also customize your monsters a bit with skills, buffs and abilities.

https://store.steampowered.com/app/1277400/Monster_Hunter_Stories_2_Wings_of_Ruin/

[Daren]

I don't think I have many metroidvanias but I can write down some of my monster collectors, maybe somebody can find something interesting:
Siralim Series (Ultimate is the newest one)
Coromon
Nexomon 1 and 2 (Part 3 is on the way :) )
Cassette Beasts
Temtem
Mython Island
Collectamon
Monster Tribe
Slime Rancher 1 and 2
Fantasy World Souls

[Darius]

Aethermancer when out?

[Xaelon]

Originally posted by Futile War:

Aethermancer when out?

Unknown, but keeping an eye on the developer's discord, social media channels and the actual forum for Aethermancer will likely yield way more useful information than asking about it in this forum.

https://steamcommunity.com/app/2288470/discussions/

[Ninjaloose]

Siralim if you like the team building making crazy combo teams (it goes very deep on this), it has no platformer part, just simple wander around and engage items/chests/baddies.
https://store.steampowered.com/app/1289810/Siralim_Ultimate/

[Friends with Benedicts]

A metroidvania monster-collector with skill trees for the monsters? I dont know any.

Even monster-collectors with skill trees are pretty rare to happen by.