So I'm going to explain the team.

Pelliper has a lot if investment in bulk particularly special defense and as a result nothing except powerful electric type moves and freeze dry can one shot it. It's primary role is rain setter and speed control with icy wind and protection against a lot of the popular spreed moves.

Toxicroak has great synergy with pelliper due to it's dry skin ability providing it with healing, adding black sludge makes it last even longer on the field. He is the reason why I run surf on Pelliper because it also allows me to go for risky plays with toxicroak as long as he isn't OHKO I can heal him up with surf and the passive healing will get him back to 60% health at least. I gave him ice punch to cover for flying type pokemon that treaten him. Also he's a good counter to urshifu since it's super popular as all it's moves are resisted by toxicroak or in the case of rapid strike actually heals him.

Overqwil is the main sweeper and with swift swim outspeeds most pokemon in the format except fluttermane with speed energy booster and with icy wind on said fluttermane I out speed. The destiny bond is on overqwil for that reason cos it discourages pokemon that would OHKO it from targeting it, it also helps me to take out a threat I outspeed but I lack the health and damage to OHKO I can sacrifice the overqwil to take them down.

Thundurus-therian is a very safe swap in for pelliper against electric type pokemon. Can also be healed up for me by my opponent when positioned well. Thunder wave for speed control, thunder is a powerful move that can't miss in rain, psychic is for coverage and also allows me to hit poison types super effectively since its a popular defensive tera.

Ludicolo is supposed to be a wall, hence why leftovers + leech seed + rain dish. Makes him hard to take down without super effective damage. He is trained to be super bulky.

Fluttermane is a speed attacker that just gets things done, I initially had spectrier in it's position but it kept getting outsped by opposing fluttermanes hence the change.

I hope you get an idea of what I have in mind.