Maybe it is more than an instance. Maybe it is an idea, a world-historical vanguard, light itself. 
actual attempt to answer (cringe)
We’ve been around for three years on a lemmy fork before federation. The lack of federation for years as well as the place we splintered off from (/r/chapotraphouse) already having a unique microculture within Reddit has given this instance, in my opinion, a distinct culture compared to general-purpose and even other hobbyist instances.
Regarding specifics, Hexbear is a vehemently queer-friendly/intersectional anti-sectarian socialist instance. Check us out 
well this is easy. she’d post so hard about redfash tankies that Bordiga would be blown off the field.