Finally got this thing to work! You're going to be hearing a lot more from me now.
So, I refuse to pick just one, but I'll give you two.
If we're talking "hot sauces you can find in a grocery story", I think Valentina is the GOAT. It's flavourful, versatile, and delicious, and nowadays I can find it anywhere. Though the flavour is mainly mexican, it's able to fit with many other food types.
If we're talking "hot sauces nobody else here is going to find", one of the first hot sauces I made was a fermented leek and ghost pepper sauce that I have never been able to completely recreate. I dream about it sometimes. I miss you, Pandora's Bottle.
Also, I have a favourite sauce from a local sauce maker but it's a small enough company that if I name it, I'll doxx myself. DM me for more info.
Picking one is difficult because different foods need different hot sauces. My generalists though are Sambal Oelek for a neutral chili flavor and Hot Yuzu Sauce for its bright fresh citrus-y flavor.
I really like El Yucateco Black label reserve. Not the spiciest or fanciest of sauces really. But it's a very tasty one that I really like having on pretty much everything from my eggs in the morning to my tacos in the evening.
Commercial or homemade? Commercial I like Mrs Renfroe's mango habanero and Mikey V's Sam Sauce. As for homemade, there's a local tamale seller whose wife makes a killer green sauce and my own fermented reaper sriracha.
I love each for completely different reasons. Don't make me choose just one, please!