Ok here's a few...!
Tubescreamer-wise, maybe a Maxon ts808 reissue, or anything by Keeley or Analogman. Or one of the less obvious boutique tubescreamer clones/'improvements' such as a Homebrew Electronics Powerscreamer (just to keep you happy Ben
) or a T Rex Mudhoney. Or you could just get an Ibanez TS-9 for half the money and see if anyone really notices!
Alternatively there's the Fulltone OCD/Crowther Hotcake school of pedals which have less midrange, more bass and seem to aim to sound like a boosted amp before you've even boosted an amp with one. I've got a feeling they could sound too bassy with your Orange.
NB a lot of the boutique Tubescreamer 'improvements' aim to give the pedal more bass, more gain and less mid, which all sound great at low volume into a clean amp (in a guitar shop...) like the OCD and Hotcake. Thing is into a loud driven amp a pedal with less bass, more mid and less gain seems to work better.
Of all the players I've seen over the last few years, in general the beginners have stock tubescreamers, the 'experts' have Keeley tubescreamers or some obscure boutique overdrive...and the pros have stock tubescreamers!
You could also look at treble boosters and fuzzes. I'm quite biased toward a company called D*A*M who make a bunch of these types of pedal. A treble booster could work well with your amp if you're overdriving it to start with, but might not be as versatile as you want. I think it would do one sound really well though. Fuzz would probably be the same kind of deal. Bare in mind with fuzz pedals or treble boosters that they're designed to work (or at least work best) with a loud, overdriving valve amp like your Orange. My D*A*M Meathead sounds awful at bedroom volume - thin, fizzy and harsh - but into a driven amp the thinness fills out, the fizz becomes fuzz and the harshness is softened and gives it a bit of clarity.
As for clean boosts, it's my understanding - could be wrong - that they all use pretty much the same widely available MOSFET design. I.e. they're all pretty similar. For me the main thing that makes a tonal difference with a clean boost is the buffer....I loved a Zoom PD-01 I used to have (don't knock it till you've tried it!) because it had a massive amount of clean/very very slight midrange boost available. The only downside was the buffer, which seemed to add a really tiny amount of top end harshness whenever it was plugged in. I don't think anyone cared about this, but I did! If I could find one again I would buy it though....seriously worth a look.
So to sum up, I'd try a standard tubescreamer, try an OCD or Crowther hotcake, try a fuzz of any sort, try a Catalinbread SCP/T Rex Moller (clean boosts) and see which direction you want to take.
