They all have been mentioned here, but I think they should be mentioned again in more detail. The probably bestest TnT family fic is bluetigers
Love Languages universe, which features three adorable Tucker children, Soval as a benevolent grandfather, a whole busload of OC's (T'Ana
) and much more importantly, bluetiger has pulled something off - a whole series of fascinating stories without the need to create artificial suspense by useless highschool-relationship-angst. Print them out and give them to a group of depressive people - bestest therapy ever.
Love LanguagesThe Logic Of TreesWhisper: Practicing with the BondYou Yre Cordially InvitedIs it Because he's Human?AnticipationHostageThe MissionThere are more of these in the archive and even more in the TriS archive. BTW, bluetiger, is there any chance to coerce or blackmail you into writing more stories with Thomas and T'Ana in them
The second Epic dealing with the Tucker family live is TLR's fantastic series. Unfortunately it has never been subjected to the services of a beta-reader, so there are a few errors in it that are obvious even to a non-native speaker like me, but none of them are severe enough to spoil a fantastic read
Little LizzieHoneymoon On VulcanAnd Baby Makes FourA New LifeThe Warp 7 ProjectI'm a bit surprised that nobody has mentioned BnB's brilliant "Road Once Travelled" series, which features Trip as a doting dad, an absolutely adorable Lizzie, Eldest Mother T'Para (one of the truely great OC's) and a really sweet romance for Malcolm with an unexpected specimen of the female variety
For Want Of A NailIn The Cold Of NightFather To The ManPurgatoryHess & KovVahklas (WIP)
That's the three greatest epics I can think of, who deal with Trip and T'Pol as parents.