Hi! As usual suspects iīll recommend both the keeley bd2, or his ts9 mod (plus or baked depending on gain needs).
Bd2: In my opinion itīs not dark at all. Stock version is piercing bright. Everybody i heard, complains that even with tone on 0, itīs is still bright.
Keeley bd2: If you are looking for an overdrive for chord work or rythm stuff, believe me, this is it. Itīs very transparent and will preserve your tone perfectly. You can go from the slightest crunch to a very furious beast (in the overdrive territory of course) This pedal works excellent as a clean boost, drive set to 0 level above unity and there you go. Also, and what i found best in this pedal, it works great with playing dynamics and the volume control.
keeley ts9: I have the baked version which has a lot more gain on tap than the plus version. I believe this is a really nice pedals for leads. I donīt like it much for chord work because it doesnīt preserve your tone as much as the bd2 and isnīt as dynamic. Anyway, ts9 based pedals with their midrangey vocal tone, stand out great for leads, cutting in the mix, with great sustain! you know that creamy overdrive so many people like. Robert makes it a perfect tool which sounds night and day with stock versions.
i hope this was helpful to you, and i hope you get what you need!
cheers!