Can somebody explain the different status effects from Killers add-ons to me?

Well there's a menu ingame where they list all of them.

You can also go here: https://deadbydaylight.gamepedia.com/Status_HUD

I believe hindered from the huntress and clown addons, and maybe one from hags addon, give a -5% movement speed rebuff.

So obv you got the list on the wiki but for anyone who doesn’t know, or for those who can’t be asked to check the wiki, I’ll try and explain em all below.

Cursed - you’re affected by a hex perk; find the totem and clenase it to remove this effect.

Blindness - You can’t see auras for it’s duration.

Broken - You can’t heal to healthy.

Deep Wounds - You’re on a bleedout timer. Mend yourself, or get others to mend you, before the timer hits 0, else you’ll go down.

Endurance - You can tank an extra hit.

Exhausted - Any perks known as “exhaustion” perks (perks which give exhaustion) cannot be used. The only exception to this is Adrenaline.

Exposed - You go down in a single hit.

Haste - You move faster.

Haemorrhage - You bleed more.

Hindered - You move slower.

Madness - Skillchecks become harder, you’re easier to track, and sometimes you’ll scream, notifying the killer of your location.

Mangled - Slows down healing speeds on you by 20% (an extra 3.2 seconds)

Oblivious - You don’t hear the heartbeat, nor are you affexted by any perks which impact the heartbeat.

Vision - increases your capabilities of reading auras.