Oh there's loads (particularly if you include pop acts) so I'll keep it down to a few headline songs I can write something about...
The Screaming Jets - Better.
Kerrang! used to really talk up this lot back in the day and I happened to record an episode of Noisy Mothers (blast from the past for any Brits...), as I often did back then, where it got played and loved it. It took me years to eventually get hold of the album it was on and the rest of their songs were almost average.
Reamonn - Supergirl.
I got introduced to this song by a German girl I went out with briefly 20 years ago... the rest of their stuff wasn't up to much, but fair play to her, this was a good one.
Inside - Stiltskin.
As far as I remember they didn't exist as a band before they recorded a song written for a jeans advert and the full album that followed it up wasn't particularly good as they tried to scrabble to cash in on the surprise success. The singer ended up in Genesis for a couple of years, which seemed an odd one to me when I found out.
b.l.o.w. - I See An Angel Sitting In A Tree Outside My Window.
When the Little Angels split up after failing to set the world on fire, which was a huge shame as their second album was brilliant, a couple of them (the brothers, at least) went on to form b.l.o.w. and they put out a very uninteresting EP before disappearing - the guitarist (the real Bruce Dickinson) eventually turned up at a University giving lectures about the music industry, although Little Angels have played a bunch of reunion gigs over the years after they reconciled at the funeral of their original drummer, who died too young (Michael Lee - played with Plant/Page).
This song wasn't really theirs and didn't even make it onto that EP release iirc (they might've used it as a b-side though), it was a pre-existing song from the lead singer they played at gigs and I managed to again catch an episode of Noisy Mothers where they featured the band and showed them playing the song live. It took a very, very long time before the internet coughed up some version of the song and there's now the singer's (as David 9 Lunas) version on Spotify. Still love it.
Gun - Word Up.
Yep, that Word Up, at least their cover of it. Kinda summed them up that their best song by a mile was a cover tune. My wife likes them a lot more than me, but that's because she's Scottish and was legally obliged to like them in the 90s.