Not every weapon is going to be good and some are quite bad when playing on your own or in a party with different weapons...

But there's a few I call "Party weapons" that have much of their downsides negated when playing in a party where everyone else is using them (or at the very least you can have more fun)

Shard bombs are for me a very clear party weapon, the more players you have littering the ground with these shards the less the empty space and timing between blasts will matter... it's definitely something I suggest people do, especially using the Shocking Salt Bomb or Scintillating Sun Shards as the Shock and Stun status will help you deal with the monsters being knocked back by adding statuses that can interrupt their attack or slow it down

The other clear party weapon are the Catalyzer gun lines as much of their downside comes from potential damage going to waste because of aggressive team members or because of knockback from other weapons.... having a whole group of players using these is a blast (pun intended)... you can have dedicated Taggers and Detonators, or have a complete free for all

Other weapons that work well in a party of identical weapons are Antiguas, Haze bombs, and Dark Retribution.. but it's not that these have downsides quite like the above pair, it's just that more players doing the same thing is pretty fun.... whether it's a flurry of rapid fire shots, enemies being locked in a maelstrom of different status effects, or just a swarm of shadow orbs swirling around

If you're getting bored and wanna have fun, try to form a group of players to pull off something like this as an event or challenge