After experimenting with other brands previously, my favourite flavours in order were, from Joylent: vanilla, chocolate, banana and then strawberry. Queal offered other flavours as well like forest fruits, apple pie, peanut and chocolate, which never really floated my boat.
Things I've tried:
A shot of freshly brewed coffee added to vanilla is great (not so keen on instant coffee).
Queal did a Straciatella shake on their Tinkering Thursday blog, which was vanilla with shredded chocolate blended in (I used a few squares of a Lindt Excellence 90% cocoa chocolate bar) and it was fabulous - probably best to keep as a treat though and not an every meal drink!
Trying a blended in ripe banana to unflavoured Huel today which is nice.
Fresh apple is on my list.
I'm thinking that frozen pineapple chunks, frozen blueberries, and frozen mango chunks might be a convenient way of adding fruit flavours.
Tempted to try some savoury flavours too.
Going to really push the boat out and try a little Hot smoked chili and garlic sauce that I've got. What could possibly go wrong?