I am asking what the best familiar is for overall everything. Main categories for me are combat use, exploration, thematics, the works really. Imps and quasits both have invisibility and shapeshifting although they are similar, a quasits can swim as a toad. You also have other things like the inkling mascot which has 18 hit points making it a bit sturdier it can also ink spray and hide though not as good as invisibility, it is a bonus action. I am aware of many others and I know I have only named a few and only some of their benefits but I would just like your thoughts. Thanks.

All things equal; I'm taking the imp every time. At low levels the imp is a ridiculously helpful combatant.  Thing was able to pick off orcs with opportunity attacks when it went invisible.  Imps also make for solid scouts at any level, and can use the Help action on some skillchecks.  

i know the imp does well, but i want to maximize potential. for example the tressym or strixhaven familiars, might be able to have significant say in this subject as well as the default familiars but i am doubtful about them, as well as the gazer and anything in between. an ideal would be a table showcasing different strengths and creatures and ranking their averages but a cannot get a working one myself.

There is no blanket right answer, and a table is going to be very arbitrary.  Much depends on the type of game you are playing in.  Not knowing specifics; I'd still go with an imp.  

Imps are the best RAW familiar, but there are individual builds that may make better use of other familiars.  You can always change what you summon so don't stress on it.

thanks, i appreciate the thought, its just that it has been a question bugging me for weeks. trying to find every possible familiar (there is a lot) and decide how best to use them, however i disagree with imp being the best raw, i think that title would go to the quasit (if we were only looking at the PHB) as it has its scare ability although it has a low save DC, with investment of the chain master, it becomes quite powerful. it also has a swimming speed and both imp and quasit will take the attack action rarely because we like our bonus actions, so the imps sting attack though useful, is not as great as it seems.

Scare ability is once per day.  If you have a good use for that scare ability then maybe its worth more to you. 

The imp offsets that with slightly more HP.  The imp has more poison damage but doesn't cause the poisoned condition.  The imp has devil's sight and Fire immunity allowing for some combos with spell effects.

Its not that the quasit is bad (its close to the imp in power), but I prefer the imp.

i hadn't thought of that, thanks. Do you think the strixhaven ones are any good or come close to the quasit or imp.

If it had darkvision I'd give sprite a nod. Invisible and +8 in stealth is pretty valuable, imp is better in a fight i guess but even the improved familiars I don't use for fighting without the right invocations. But without darkvision its a harder sell, it really helps in stealth missions.  As is the imp just nails it better overall despite the drop to +5 in stealth.

The bone i have to pick with the sprite is the 2 in health. I'm not too obsessed with my familiar being a combat machine, but i don't want it taken out by a stray arrow and with immunity's and resistances, it can get past AOE spells and take the help action or whatever fun abilities it has, such as the ink spray of the inkling mascot. I think the imp is a strong contender but i think there are some more unsung heroes that i want to bring into spotlight.

The imp has hands, and therefore can use items. It also has devils sight and turns invisible and flies. 

pair it with voice of the chain master invocation, and you’ve got the best scouting drone in game.