Favorite Type: Normal. Despite being considered supposedly "The second worst pokemon type" according to "The definitive ranking of pokemon types," because "it doesn't hit weaknesses, and has no resistances except for a ghost immunity". That doesn't stop Blissey, a normal type, from being the best special wall in the game. The fact that all the way back in Gen 1, they still have by far the best coverage options compared to every single type, and support abilities as well. And as far as monotypes go, Normal types can be surprisingly one of the best. Oh, and Gen 1 normal types were the answer for nearly invincible psychic types. Even in the later generations, the normal types were still usable. Really, they only suffered because fighting types started getting STAB on 120+ base moves or higher, as well as some ridiculous power creeps in Gen 4. In gen 1, Tauros, Chansey, and Snorlax were real threats throughout the first 3 gens, with Tauros ruling Gen 1, Snorlax ruling Gen 2, and Chansey still getting use in Gen 5 and beyond. Gen 2 introduced us to Whitney and her Miltank, which required a bit more strategy than any other gym leader before or after, and it introduced Blissey, the best special wall in the game, and gave Snorlax the amazing special defense increase. Even Ursaring was strong, and porygon2 was a powerful pivot. Even questionably, Girafarig proved to be a tricky but very useful typing, with psychic/normal that can use earthquake and crunch, and is one of the few baton passers back then. Gen 3 didn't have good normal types introduced honestly, with the horrible truant Slaking making the most impact as a pure normal type, and swellow being the only decent normal type, but every thing else was outclassed (Zangoose is eclipsed by ursaring) or really horrible (Kechleon, spinda, linoone with no coverage) and it removed all of the best normal types except for Dodrio, and, by virtue of great dual typing, Girafarig. But Gen 3 gave great abilities to the old normal types, like intimidate, and coverage, making granbull pretty threatening. Gen 4 gave Staraptor, which while was part flying, was also a normal type with intimidate, and close combat/u-turn, while acting as a beautiful fighting type deterrent. Now, are there better types out there? Yes, at least beyond Gen 2, though they were still respectable in Gen 3, but unlike my least favorite type, it never found itself in a position of uselessness.
Least Favorite: Fire. Get ready for a long, possibly controversial rant, as I really need to address something about fire types:
-Contrary to the "Definitive type ranking, which labeled fire types as number 2, they were almost unusable in Gen 1 apart from the handhelds. But even there, fire typing is a type that is designed to suck against the first 2 gym leaders, acting as a poor method of being a "hard mode," and losing to the easiest gym leader.
-While you could claim that fire was a good coverage type in gen 2 and beyond, which I won't deny, you can't do this for Gen 1. It is literally the worst special attacking type in the game, because Ice, and Psychic outclassed it, hitting everything that fire types could hit harder, but it is the only type in the series that removes an enemy's status effect, which was in fact, the best status effect in the game that is rare to get on an opponent. And the fire type is a pokemon type that removes the rare status infliction.
-Oh, and fire didn't resist ice back then, and ironically, ice was actually a solid defensive typing back then too, with Jynx having the partial psychic typing and lovely kiss.
-Every type, even ghost (normal immunity), dragon (resistances), poison (surprisingly useful resistances despite psychic weakness), could do so much more. And surprisingly, there are non-legendary bug types, which was extremely limited offensively as a type, could have their uses: Pinsir (swords dance, slash, seismic toss, guillotine) and especially venomoth (Stun Spore, sleep powder, psychic) could still outclass fire types in many roles. As for offensive moves, a fighting type move is still more usable than fire blast, called Seismic Toss.
-Fire spin is the least accurate and least strong wrapping move as well, with its only benefit is to hit gengar, for pathetically small damage. Not to mention the advantage of the fire type wrapping move is rendered null, since most fire spin users can't outspeed Gengar unless they are one of the two agility users.
-And apart from moltres, flareon, and ninetails, their surprisingly mediocre specials drag them down even more, not only making them weak to special moves, especially psychic types, but that means that Grass types can tank their fire moves too. I have seen grass types defeat fire types one on one, and Erika is still a formidable gym leader because of the difference in special attack and defense, among wrap and status moves.
-Not to mention that Fire types are the only type to get completely walled by 3 types of pokemon in Gen 1, and don't have any method of status apart from toxic or body slam (which nearly everything gets) to hurt them. And burning a recovery user is a guaranteed death sentence, as if unfreezing your enemy wasn't bad enough.
-And lets put this into context: who is still the worst eeveelution? Flareon. The worst of the legendary beasts? Entei. The worst of the really big legendaries in GSC? Ho-oH. Gen 1 Legendary birds? Moltres. What do they all have in common? Fire typing.
-Even when Gen 4 gave the beneficial physical special split, it also introduced stealth rock. Oops. That powerful Volcorona? Has the absolute worst weaknesses to entry hazards, out of all 700+ pokemon. So fire types can never play a defensive game, and can be very easy to wall, unless you have a hidden power move, which doesn't add much since every pokemon type can learn hidden power just as well, if not better.
-As such, fire types tend the be the worst to monotype, especially in Gen 1. (The amount of times Blaine gets completely ruined by almost everything, even grass types and bug types, is just embarrassing.) And the fact that apart from fire/fighting, which barely buffers against rock types (they carry earthquake after all), there is no dual typing made that can buffer the weaknesses. I could've forgiven fire types being horrendously bad in Red, Blue, and Yellow, if they had made a fire/grass type, but they still haven't, and introduced the Rock/Ground Magcargo, who holds the dubious honor of having the worst type combo in existence.
- And it seems that fire types can't avoid 4x weaknesses, especially to water, ground, and rock. And even with houndoom having a cool design, and useful coverage typing for dark types, the dark typing doesn't really help the fire typing apart from scaring slowbro and starmie, just a few of many more enemies fire types have.
- And just as you think the sunlight helps them out, to counter water types, as well as a rapid spinner, they still have to beware of earthquake users, and if they are part flying, electric types and simple rock type attacks.
-To say that its an overrated type is beyond an understatement, as at its best, has so many problems, and at its worst (Gen 1) just horrendously bad. In a way, Gen 1 fire types are much worse than Gen 1 fighting typing in terms of terribleness (At least the fighting type move Seismic Toss gets used in Gen 1 competitively, ironically from a few psychic types and chansey, and is the only thing that prevents Gengar from completely walling fighting types, fire types was bad both defensively and offensively in Gen 1, and are still really bad defensively thanks to stealth rock, and numerous popular weaknesses).
-From Gen 2, fighting types became amazing in both moves and pokemon, but fire types honestly only became useful as a special coverage move at best, and despite some really overpowered stats and movepools in gen 4 and beyond, are still not as threatening as other types. There is a reason why fire types needed a resistance to fairy, because they have so many flaws, any additional advantage helps.
So yeah, fire types are my least favorite type, because of the above reasons.