If we're talking self-inserts with original character romances and alliances, I keep circling back to one particular dynamic that hooked me. A story where the SI, instead of hitching up with a canon companion, builds a relationship with an original settler leader in the Commonwealth. The alliance wasn't just a romance subplot; it was the core political mechanic of the fic. They had to negotiate water rights with Diamond City, deal with rogue synth incidents, and the romance grew out of that shared, stressful leadership. It felt grounded because the OC wasn't a flawless hero, but someone with their own ambitions and a deep distrust of the Institute that sometimes clashed with the SI's more scientific curiosity.
The alliances with smaller factions, like a group of reformed Raiders or a Minutemen splinter group, often felt more meaningful than just aligning with the Railroad or Brotherhood. Those fics spend time making you care about OCs who represent the everyday people of the wasteland. The romance, when it happens, tends to be a slower burn, born from shared survival rather than instant attraction. I've drifted away from fics where the OC love interest is just a combat buddy; the political ones where building a new settlement is the central conflict usually handle it better.