i've speedrun games such as Portal and Hello Neighbor and i'm really looking for a new one any recomendations?

Poppy Playtime: https://www.speedrun.com/poppy_playtime
Karlson: https://www.speedrun.com/karlson_itch_io
Muck: https://www.speedrun.com/muck
Slime Rancher: https://www.speedrun.com/slime_rancher
Granny Series: https://www.speedrun.com/granny_series
Roblox Arsenal: https://www.speedrun.com/roblox_arsenal
Here are some first person games

I'd suggest Layers of Fear, it's a pretty easy game to pick up, (almost) no glitch to learn, just game mechanics and optimization. It's a fun run and progress comes really fast in the beginning!
https://www.speedrun.com/layers_of_fear

There's also Observer from the same devs
https://www.speedrun.com/observer

And because I love horror games... Take a look at Alien Isolation!
https://www.speedrun.com/ai

Minecraft

There Is No Game

TING isn't a first person game

It isn’t even a game

Since you mentioned portal, here are some similar fast-paced games:

All the halo fps games
Mirrors edge
Doom 2016
Ghost runner
Severed steel
Back 4 blood

Grey box testing its not a online shooter game but its a simulation

The thread is first person games, not necessarily shooter games. Anyways, I can vouch for Grey-Box Testing

The Ultimate DOOM
DOOM II
DOOM: TNT Evilution
DOOM: Plutonia Experiment
DOOM 3
DOOM 2016
DOOM Eternal

Damn you love doom

I also advocate for DOOM

DOOM 2016 Any% (Difficult but very cool)
DOOM Eternal Any% Restricted (Not super difficult to pick up, very cool)

The 100% categories are also very very good, but have a steep learning curve due to the amount of memorization and difficulty.

Also

Titanfall 2 (If you're familiar with Source movement, pick this one up)
Mirrors Edge (Steep learning curve if you want to learn everything, but very comfy if you learn the basics and just decide to dive right in)
Mirrors Edge Catalyst (Still pretty fun, much simpler)
Ghostrunner (Unique high inputs per second movement)
Severed Steel (100% Destructible voxel environments make for cool routing)
Resident Evil Village NG+ Casual. (3/4's super comfy, 1/4 fucking terrifying)
POST VOID (This game is $2, pretty difficult but very comfy)
Prey 2017 (VERY easy to pick up. Learned this as my first speedrun and was able to start running within an hour)
Fallout New Vegas (You zoom forward by reloading a revolver, what more can i say)

So there's a few recommendations, honestly I'd recommend just about anything that I've run on my profile

@MetaMeta why are you so cool??? lol

Minecraft 4K
most under rated game ever

No

bitlife