Snarl - commonly used in doubles formats, Snarl is a great way to lower the Special Attack of multiple opponents. It works well on Incineroar and Arcanine due to them also having Intimidate, lowering the Attack of the opponent's.
Haze - while Haze technically doesn't lower stats, it resets your opponent's stat changes, meaning it can prevent set up sweepers like Bisharp, D-Dance Dragapult, and Moxie + D-Dance Gyarados from taking out your team. A lot of Toxapex run Haze, since it's quite bulky and can survive attacks from boosted opponents.
Clear Smog - basically the same as Haze, but it also deals damage. You can find it on some Amoonguss sets (such as my own).
Sticky Web - indirectly lowers the Speed of your opponents, as long as they're not holding Heavy-Duty Boots or a Flying type. You'll want to watch out for Bisharp (Defiant), Rapid Spin users, and Defoggers, however, Sticky Web is still a great move.
Parting Shot - a form of pivoting, Parting Shot lowers the opponent's Attack and Special Attack while switching you out. It's most commonly seen on Silvally and Incineroar (since it's an Intimidate pivot).
Fire Lash - pretty good on the Pokemon that learn it, such as Centiskorch. It's probably not as good as the rest of the moves on this list, but the Defense drop is nice.
Close Combat - you didn't really say whose stats you wanted to lower :P. Close Combat is an excellent move, though it lowers both the Defense and Special Defense of the user.
Thunder Wave - a great, annoying move. It can leave the target fully paralyzed, plus it cuts the opponent's Speed in half.
Will-O-Wisp - similar to Thunder Wave, but it cuts the Attack of the target in half. Additionally, the burn deals damage every turn.
That's all I can think of right now, I'll see if I can think of any more.
Hope this helps! :)
