I don't think there are any genuinely bad types. But I'd say Bug is the least useful out of all.
Forgot I even posted here, but I take this back completely. Everything, as in both when I said Bug was the least useful type and that there are no bad types.
Normal is bar none the most useless type in the whole game.
There are plenty exceptions. The dual type Normal mons that are paired with other types, including Normal/Flying mons, those are all cool. Everything that is considered amongst the best pure Normal are also cool. And unpopular opinion incoming: I think the route 1 two stage guys are also among the better ones, as they are probably going to show up before the best Normal mons do and some could be useful for early game, and since you probably invested EVs into them, you are allowed to take them far if you are particularly attached. And there are also a few miscellaneous Normal mons that I did kind of enjoy using.
But the issue is: if you aren't amongst the best ones like the stuff I mentioned, or if you don't have an interesting gimmick or ability, then you're gonna get overshadowed. Outclassed to the point I'll be like "Man, why can't I use a BETTER Pokemon who can actually deal super effective STAB?". And truth be told, if someone doesn't resist anything and doesn't have an advantage against anything, then it's best that they better have excellent stats or ability or gimmick, or even a reason to even be on the team.
Seriously countless times I added a Normal mon to a team and even if they were the
best Normal mon I had, I ended up rejecting it because due to having no particularly good stats
and can't have any type advantages through STAB, I rejected them for mons with similar or even slightly worse stats, but ended up with a significantly more fun time.
I heard the excuse that this is all made up for the fact most Normal mons have great movepools. And true, it helps… all the already awesome ones. And for the outclassed ones all the coverage is either stuff that won't help it much or go off the worse attacking stat. And overall, only
select Normal mons have these particularly massive movepools anyway, so this isn't a great argument.
I mean Ice also has many problems that even others on this thread mentioned. It's a lot like Normal where it also for some bizarre reason has barely any resistances and it only resists itself. But if I had to choose between a Normal mon and an Ice mon both of which have similar stats, I'd go with the one that can actually deal super effective STAB.
Tl;dr, with several exceptions, Normal has got to be the most useless, bottom of the barrel type that underwhelmed me countless times. There is literally only one Normal evo line that I think is awesome and every other type has at least two. I mean there are many pure Normals that I was kinda attached to due to having good experiences with those, and there generally aren't any Normal mons that I actually dislike, but still!