Crouch Cancel -> Dtilt -> Jump Cancel Grab is a favorite of mine.
You can extend that into so many options such as:
Fthrow for the kill or gimp
Dthrow -> SB tech chase (worst case scenario you end up opposite him on stage)
Dthrow -> DACUS tech chase (varies based on weight and percent)
Bthrow -> Rising Nair off stage for the gimp
Uthrow -> Sour Uair -> Sweet Uair
Uthrow -> Uair -> Fair
There are SO many options, you just have to figure out when and how to use them. Wario can set himself up for a ton of 50/50 situations as well just by landing a bite. If you know what a tomahawk is, that's pretty much how I bite. From there I usually tech chase with more bites or a DACUS/Side B. A tip for biting is to short hop every bite and get good at wavebouncing/Breversing. You can completely throw off your momentum by jumping away and then Breversing right back at them with a chomp. The best part about Wario is how creative you can get with your mobility!
Also, platforms are your friend. Uthrow them to a platform and then tech read with a bite. If they're high enough percent, use your air mobility to strafe back to center stage with them in your mouth and toss them to the other platform. Yoshi's Story is one of Wario's favorite stages just because of this in my opinion.
Finally, footstool combos are so good for Wario. If you don't already, I recommend rebinding L, Y, X, or any other button you don't use to one of the taunts just so you can footstool. The timing and placement of footstool is kinda weird, but once you learn where it is, possibilities start opening up.
Some footstool combos:
Bite -> Footstool -> Dair (Works on heavies at low %, RIP Bowser)
Dair -> Footstool -> Dair (Works amazing in Wario dittos if they miss tech)
Fair -> Fair -> Footstool (Fairs offstage, footstool to meteor, dair if necessary)
and I've even seen Reflex footstool out of Nair
Footstool can also be used to gimp your opponents, or set up a dair offstage if they meteor cancel it.
One thing to note is that you CAN tech footstools, so if your opponent knows this it could ruin the Dair combos.
That's pretty much all I can think of at the moment. If I think of anything else I'll revisit. Also feel free to PM me if you have any questions. I'm not very good, but I like to think I know my character