Oof, currently in a slump myself and it's really difficult to find something that gets you out of it but here are some thrillers that were very thrilling, interesting, and engaging for me.
Fuujinshi - It's a short watch but very well made with amazing fight scenes and a pretty solid plot. One of my favs
- Big Mouth - Very thorough in thrill, interest, and high stakes (bonus points: Good OST). Never really a dull moment but beware of the ending... Spoiler: sad ending
- Bad Guys - Anothe very solid one with lots of high-action and thrill but it did have a bit of a weak ending.
- The Veil - Really good story, mixes a bit of psychological elements with high action and thrill (bonus points: Good OST).
- Kingdom 1 & 2 - A bit slower than the others and it's historical but also, thrilling, interesting, slight horror elements.
- Vigilante - A bit weaker than the others but one of those gratifying watches. High action, thrilling, just overall a good time.
- Memorist - Also very high stake, thrilling action with supernatural elements. Ending was also a bit weak but the rest was good.
Hope you find something you like and I'll definitely be keeping an eye on this thread for myself ^.^