Sure, why not. My Smash Bros. music lists are going to be organized a wee bit differently, though.
I may as well give out the warning that the only Smash Bros. games I've played are the first 3, which is probably skewing my results.
First, my favourite menu theme:
1. Smash Bros. Brawl Menu
Maybe all that time I spent on Brawl's menus helped, but I still love that 3-3-3-3-2-2 rhythm and its relative consonance compared to the previous menu themes. I personally don't find the succeeding games' themes to be quite as catchy.
Next, my Top 5 Smash Bros. Remixes:
5. Spark Man Stage (Smash Bros. 4)
This gets major points for being the only Smash Bros. 4 remix I remember. Admittedly, Smash Bros. 4 didn't bring in nearly as many remixes as its predecessor, favouring a large influx of raw-ripped themes instead.
4. Shin Onigashima (Smash Bros. Brawl)
I've read that the Japanese find this remix as hilarious as we find the Brawl Gourmet Race remix to be--reasonably famous, traditionally decidedly NOT heavy metal music remixed into heavy metal form. Screw the original music, this folk metal remix is great fun.
3. Meta Knight's Revenge (Smash Bros. Brawl)
With big band jazz-style remixes like these, who needs Meta Knight's theme in the series? (OK, I'm a bigger fan of the Halberd themes anyway, and I bet quite a lot of other people share my opinion.) This was one of the only themes I remember from playing Smash Bros. Brawl (note that I did that before plunging headlong into its OST), and it's one of the themes that got me into investigating Kirby series music in earnest.
2. Battle! Team Galactic (Smash Bros. Brawl)
The Team Galactic Grunt theme was one of the only themes I remember from playing Pokemon Diamond (admittedly, I probably played half that game with the sound off), and this remix brings in some great instrumentation changes. Rumours are that this remix is also faster.
1. Corneria (Smash Bros. Brawl)
Admittedly, I like Star Fox's Corneria theme a lot, but this is definitely a remix that improves on the original. No more G major tonic chords in a G minor piece, for starters! The extensions are also a nice touch instead of merely being annoying.
Finally, my Top 5 Themes Introduced to Smash Bros. Unmodified:
5. Those Who Stand Against Our Path (Xenoblade Chronicles 2)
I find Xenoblade Chronicles 2's battle themes to be better overall than Xenoblade Chronicles's, so I was glad that one of my favourites made it into Smash Bros. Ultimate. Come on, You Will Recall Our Names...
4. Dangerous Dinner (Kirby's Return to Dream Land)
I was hooked by this map theme the first time I listened to it, and I'm so dang glad it's in Smash Bros. Ultimate, even if I can't quite figure out why.
3. Mechanical Rhythm (Xenoblade Chronicles)
It's over 3 minutes long and loads of fun! Par for the course for Xenoblade Chronicles, right? ...OK, I find that game's battle themes to be not so catchy overall, but its best still blow loads of battle themes out of the water. The double-loop-with-extras structure is a nice touch.
2. You Will Know Our Names (Xenoblade Chronicles)
...OK, I'll admit that the Smash Bros. series was
the way I was first exposed to Xenoblade's music. This theme's tendency to turn into a nearly melody-free heavy metal jamming session took a bit of getting used to for me, but this stuff ends up being pretty darn memorable in the end.
1. Boss Fight 1 (Kid Icarus: Uprising)
Compact and vibrant, this boss theme also got me hooked from first listen, and it's never let go since.