Brock is an iconic character, but I don't think his Pokémon are really iconic, except for maybe Croagunk and that is mainly for the gag joke in DP.
Onix > Croagunk. I like his Croagunk, but if you'd ask group of 30 year old people if they remember Brock from Pokemon - and if they remember what pokemon he had, people would either say they can't remember what is was called or Onix.
The first gym win with Onix only being defeated because Pikachu set off the sprinklers in this show is iconic. Croagunk is a gagmon that came into the show way too late in its run to be anything near iconic.
1. Ash/Pikachu vs. The Spearow flock.
2. Onix binding Pikachu and Ash giving up only to win because of sprinklermalfunctions.
3. Charizard vs. Magmar.
4. Basically anything with Mewtwo.
5. Charizard sleeping costing Ash his league match.
There are many more memorable moments that I can mention (heck I personally think the Yaz vs. Kaz-gym episode is iconic), but the above pretty much are a step above and instantly visually recognizable. Anything after it doesn't really come close to becoming iconic. Yes, that includes big achievements like Pikachu vs. Dragonite, Charizard vs. Blastoise, BlazeNape vs. Electivire, Ash-Greninja vs. M-CX - which are all huge moments, but if I were to ask a 30yo if they ever watched the anime, and if they would say yes, I'm pretty sure they could recall the above 5 moments. Or if you'd show them a visual reference, they would know the story.
Almost 10 episodes since Drizzle appeared after evolving. I guess it wont appear again until it evolves. I am forgetting it exists sometimes ngl. What a way to treat a starter.
Oh yes Gengar is reaching dangerous Palpitoad levels of being used in battle
Palpitoad can only (effectively) be used in reference to appearances outside of battle. As there are Pokemon that battled less then Palpitoad, like Melmetal, Goodra, Gliscor, Kingler and Muk.