Maybe I went overboard with all the silver bordered cards but I still think:
Mise (restricted)
Mana Screw
Gerrymandering
Once More With Feeling
Goblin Tutor
Staying Power (probably with an errata of some sort)
Strategy Schmategy
World Bottling Kit (maybe in need of errata and maybe restricted)
Blast from the Past
Uktabi Kong
and Goblin Bookie are fair enough to play.
Mise would obviously be restricted for power level reasons but it certainly fits within the rules of the game. Then you could run Ancestral, Mise, Brainstorm, and Ponder as your 3 draw 3s for
. This is also why I would keep brainstorm and ponder restricted.
Mana Screw Broken artifact but not Mox Lotus or Gleemax broken. Way worse than Sol Ring and Mana Crypt but would probably see play and could warrant restriction, who knows.
Gerrymandering was supposed to be in Alpha anyway and was cut but the card doesn't seem like it would be too confusing or time consuming if anyone even bothered playing it.
Once More With Feeling has already been reprinted as Sway of the Stars in a different color and mana cost. The WWWWW Needed to Cast this probably won't lead to anyone playing it but still fits within game rules and isn't too silly.
Goblin Tutor This adds dice rolling effects as a mechanic which isn't too harmful as long as a bunch of cards aren't printed with dice rolling effects (use coin flipping as precedent).
Staying Power This was also supposed to be a real card in Mirrordin block, I think. It was too much of a rules nightmare so it was saved for Unhinged. With Humility already legal though and several cards having fallen victim to erratas this could function if it was errated to only apply to certain effects and not instants or sorceries.
Strategy Shmategy See above reason for Goblin Tutor. Plus this is actually kind of powerful.
World Bottling Kit City in a Bottle is legal and so is Apocalypse Chime. This was another card developed for a real set (I think Mirrordin block again) but was decided it would wreck standard too hard. I think set hosers are interesting and this is the only powerful one. Think of naming Urza's Saga or Alpha/Beta/Unlimited or something. This may be restrictable.
Blast From the Past Lots of abilities, could be confusing but there are more confusing cards out there that are legal
. Doesn't break any rules. This could have been some ridiculous card from Time Spiral.
Uktabi Kong Another card that is fair and falls within game rules. It's an inside joke but not too goofy of a card.
Goblin Bookie See above again.
I doubt most of these cards would see major play (aside from Mise) and I really just hate the idea of 2 entire sets that contain some cards that fit within game rules and precedent being completely banned. Most silver bordered cards should be banned, most are joke cards that only apply to multiplayer casual games or clash with the rules completely. I just hate to see the following sit in non-playable limbo when they could be played.
It could be fun to playtest these in casual vintage or something as I realistically don't see these ever being legalized
Also remember that Mindslaver was supposed to be an Un-card, The Cheese Stands Alone got a functional reprint and Once More With Feeling got a semi-functional reprint and most of the cards I've named were supposed to be black bordered anyway and fit with the rules and aren't too jokey. The rest of the cards on my "unbanned silver bordered" list I couldn't care less about. I just think these have strong cases and most probably wouldn't be viable anyway but again it would just be nice to have the ability to play a few Un cards in real tournaments. Sort of like when Portal and Starter cards were banned, it upset me to see so many potential good cards sit around gathering dust.
Also, I would change
Zodiac Dragon back to it's original text and restrict it and probably restrict Squee or Bazzar also (probably Squee actually because Bazzar lets a lot of different decks operate aside from ichorid, like Madness, Threshold, and DragonCombo and they would have 1 Zodiac Dragon and 1 squee to feed their draw engines. Restricting Bazzar doesn't just hurt Ichorid. If I were to restrict anything to hurt Dredge while letting other decks flourish it would be Serum Powder.)
