Did this post just get hella necro'd? Seems like it did, but if the above is true then I'll cast in my two cents. I can narrow it down to like, 6, right now at least.
6. Brushes. Either kind. For messin' around and stuff I consider brushes the msot fun weapon in the game. They aren't higher because they are a bit obnoxious to use in a lot of situations and aren't as satisfying otherwise, but definitely fun.
5. Squiffer. Quickly becoming something of a favourite of mine after talking tactics and strategy with Lean, I find the Squiffer is kinda like the opposite of the Brushes. It's not as fun, but it's very satifying to do well with. I sometimes host all-Squiffer turf war lobbies on r/Splatoons discord or my team server.
4. Custom Dual Squelcher. This one is actually my true main, it's my highest ink'd weapon with my favourite kit and my most solid consistent weapon. It's not higher becuse frankly it's kinda boring, but it's just so solid and comfortable to me I use it like, alllll the time. No weapon is truly boring when playing Splatoon however.
3. Sloshers. Good old bucket. I mean, do I actually need to explain to you why sloshers are fantastic? Now I don't think so but I will anyway. Get ink, dump it on enemy squiddos. Nothing like having a vantage and plopping buckets of ink on your enemies.
2. Rapid Blaster. Another one like squiffer, not terribly fun in comparison to the rest of this list(Which still means really fun) but immensely satisfying. This is my most aggressive weapon and I have the most general success mounting offensive actions with this weapon. I tend to get a lot of kills playing with it, and I have an adorable gear set for it (The complete squid girl). Not even the squiffer makes me feel as skillful as getting a high K/D with the Rapid.
1. Splatlings. Probably the most balanced of all the weapons listed here between fun and skill and effectiveness. Generally though the best thing about it is the cool aesthetic of being a big-*** weapon that shoots a lot v(▼ω▼メ)ゞ. I like heavy weapons, and generally being heavy weapons support or just good old support in general in most games and that's tru eof Splatoon too, hence my favourite kit being Beakons and Wail. I like the Heavy and Hydra most because I can just be a weapon platform in a lot of situations and turf hard and lay down suppressive fire from a vantage. In other games, I'd like being the healer, or artillery, or utility and in Splatoon I like being a big old gun with an Inkling attached.