In before "all of them."

Like a few others I'm tooling around with some alchemy reworks, and a big part of it is eliminating useless potion effects. For me "useless" encompasses probably half or more of the effects out there including:

+Fortify magicka/health/stam (why wouldn't I just chug a restore X potion instead?)
+Regen magicka/health/stam (Base regen which is what these pots scale off of is gimped in battles anyways and is more than sufficient outside of battles)
+Fortify carry weight (it's just a bother to reapply this potion at five minute intervals when you could just drop that seventh dwemer helmet on the ground instead)
+Fortify any skill outside of 1H/2H/Marksman/Destruction/Smithing/Enchanting
+Waterbreathing (to my knowledge there is literally nowhere in the game you ever need to go where this is necessary)
-Ravage magicka/health/stam (Why do I care about shaving max stats off a guy who's gonna be dead 10 seconds from now?)
-Damage magicka/stam (It takes several pots of either to drain a single guy's respective stat pool... in the time that takes I can stack health damage poisons and just kill them outright)
-Lingering damage magicka/stam (ditto)

What do you find yourself never using?

any poisons, and anything I can't make a profit on

All of them.

Great joke!

Easier to tell which effects I do use:

Fortify+restore health/magica/stamina. Two in one.
Resist frost/fire/electricity. Preferably single effect, I just can't keep in mind that my resist frost potion is actually called fortify sneak.
Fortify enchanting and smithing. Stored close to respective workshops.
Fortify carry weight, just gotta have a few of those for a rainy day.
Invisibility. Used only once so far, but it's good to know I have some just in case. Hard to sell those anyway - merchants can't afford to buy even one bottle of it, especially if it's with another effect.

Everything else is there for grinding speeechcraft.

It is probably not a joke. The joke is alchemy. Ultimate healing potions are thrown at your face 50 at a time, same with Ultimate stamina and magica. Potent poisons and paralysis stuff abound in falmer dungeons. Blacksmith elixur and Enchanter elixur is sold off the shelf. Tons of potions are all over the place. I really can't get into alchemy until I chug all my insta perfect potions.

If potions were rare or expensive I might consider it. But free options and excellent quality abound, alchemy has to be a hobby in this version.

Seeing as I'm not an alchemist I must everyone except restore health/magica/stamina and cure disease.

I actually use most of them. In regards to fortify health, it's actually very useful. Say you're a thief, with not much health and you're fighting a giant. Now, health potions are useless because he just 1-shots you. So You use fortify health so that you can barely survive a hit and then just restore your health and keep on fighting instead of going to the moon.

It is an awesome effect to combine with restore. Fortify magic + restore magic in one potion is very effective.

Agreed on the +regen potions, given that the in-combat rates are so craptastic that fortifying them is worthless, and I also don't see much point in Fortify Magicka or Stamina since you tend to be enchanting to cover them anyway. Also not a fan of Fortify Carry Weight, but then I modded things such that I start with a much higher capacity and get much better returns on Stamina increases.

Fortify Health is another matter; since it's generally the one resource you cannot afford to deplete, the more you have the longer you will last. That does depend on play-style, though; a stealthy sort will have much less use for it than, say, a 2H melee character, since the idea is to not get hit in the first place. As a result I haven't used it much so far, as my first two characters were sneaky archers, however my current one is 2H+Destruction so will be using it a lot.

Fortify potions other than the ones you mentioned do have uses, although in the cases of Illusion and Conjuration there are hard caps in place for some spells that the potions can't help with. I don't use them myself, since there's rarely any need for the boost, but then I always use enchanting; someone who doesn't would have use for such potions, though, since they'd want to maximize their Cost:Effectiveness ratio in order to conserve magicka.

I'm thinking of doing a similar Alchemy overhaul, since I never use poisons due to the combination of their single-use-only nature and the fact that a highly smithed weapon makes any poison damage peanuts by comparison. As such, I plan to phase them out and reassign a bunch of the effects I will keep to have a more even number of options between them, as I don't really need 17 options for Restore Health but would like more than 3-4 for some of the more important ones.

A shorter list is what I do use. Fortify Barter, Enchant, Smithing, Health. Paralysis or slow or frenzy coupled with damage health. Restore health. Damage Health. That's really about it.

I have never used a stamina improver (I play an archer and stamina is not an issue)

I have never used any of the "weak" ones. I always meant to, but forgot everytime I went into combat. Now I'm high enough level that I don't use any potions at all. I carry around some health potions... but can't remember when I last took one.

Before I discovered the shadow stone I used to mix invisibility every chance I could.

Only potions I have ever used are healing, fortify enchants and fortify smithing. I tried a couple of poisons but I see little benefit for my play style.

No poisons except paralysis and slow. Fortify any skill I don't use (obviously), anything to do with stamina.
Most useful for me, fortify health, followed by fortify destruction and fortify one handed.

OP can never INB4, opinion invalidated.

Only two I use on this character are +smithing and +enchanting. I don't think I've even used a healing potion yet at level 44.

I've used pretty much all with my mage, although i never bother with potions such as fortify pickpocket, but i do use fortify health if i am low on health potions.

i made a crazy potion with crimson nirnroot, jarrin root and human heart, it made:

poison 2704
damage magic regen 100% 68 secs
drain stamina 122
drain magic 41

i had alchemy about 85ish with 35% total added to my alchemy skill with gear.

i was a thief so i only used poison, slow and paralyze...with the prevelance of potions throughout skyrim i really didnt need any of them and even on master i hardly used them...