I assume that like most other people here, you dont want to hear about Bombazar and Bombazar decks?
I guess i can give you two decks then, one with Bombazar and one without. The absolute best deck i have built and probably about the best deck you can build in tcg, is my Bombazar Blue deck. Yes it is very standard and well known, so i cant really say that it was my idea. It is a very straight forward aggro deck, that applies constant pressure on your opponent, so that they usually end up just playing defensively i hopes to stay out of Bombazar's range. However they usually just fall short, as the deck is built to deal with blockers and even opposing aggro, and then just finish them off as soon as your field is big enough. The fact that you have Bombazar as your finisher, in a deck like this that would be a solid aggro deck even without Bombazar, just makes the deck broken. As mentioned you could probably beat a lot of decks with this deck without Bombazar, but then you have a speed attacker with double breaker that grants you a second turn after playing it, which is just unbelievably good. It is also soooo easely played, as you have 4 and can throw one of them down as mana, to avoid it from being discarded and then play it with soulswap already on turn 4-5 (due to mana accel + swap). It is extremely effective, and other decks without Bombazar just cant withstand the pressure followed by Bombazar and Twin Cannon. You could also run Corile in this deck instead of Surfer, as it works great with Soulswap and since this deck really appreciates Coriles removal effect, and the way it delays your opponent (when they are already very pressed for time). However i chose to run Surfer instead, just to have 8 triggers and to function better against opposing aggro and Bombazar decks. The deck can take a loss here and there, but typically it will just win very easely against pretty much all other deck, assuming you play it correctly.
Bombazar aside, as we all know it is the best and most broken card/deck. If i have to name the best all around deck i have ever made without Bombazar, it has to be the RUB control deck i have today. It does well against all matchups, and just plays all the best staples from the 3 civs it runs. The water civ is the true backbone of the deck, backed up by the Fire and Dark staples. It has a good early game with Emerals, Squitos, Stream, Hulcus etc. It has the best midgame possible with cards like Corile, Merfolk, Loco, Clamp etc. Not to mention a great lategame with Bolmeteus, Apocalypse and Miraculous Meltdown as insurance. The deck has great hand advantage, and really has no bad matchups. You could also easely add Velyrika and Bazagazeal to the deck, especially if your facing more control decks rather than aggro. However against all kinds of different decks (both aggro, control and rush), i like this build the best. It wins just because it plays better cards on average than your opponent, it doesnt depend on certain cards to work, and its gameplan has zero risks about it. There is really no bad hands for this deck either, as its structure is just so well balanced, that it can always do something. Meltdown is also amazing and can win you a lot of games where you get unlucky or just lose in other ways. Just and awesome deck, full of stability and versatility.