Stealing Hilda's format 'cause it looks sweet!
Typhlosion - If offered the typical reborn choice of every starter from every main series, the starter I would undoubtedly pick for my own personal journey is Cyndaquil. It's my most used starter from my most played generation, and definitely my favorite. I also like to think that it's one pokemon that would stick with me through thick and thin, and one that I'd never let off the team. My Pikachu if you like.
Lilligant - This pokemon is one that looks jaw droppingly gorgeous (not like that) while maintaining a simple design. I also adore the idea of it, with own tempo, sleep powder, quiver dance, and petal dance it seems like the devs are trying to send a message about how to use this pokemon. A message that (while I'm not usually keen on sweepers) is too cool to pass up when found in conjunction with its stellar design.
Mega-Mawile - My favorite mega, my first mega on the competitive scene, and a contender for one of the strongest non legendary megas designed thus far. What reason do I possibly have to not include it?
Dragalge - When I first scrolled through the list of pokemon introduced in the 6th generation, this is the only one that stood out to me. And boy did it stand out. Aside from the attention grabbing aesthetics there's also the fact that it's Poison/Dragon, has adaptability, and both good natural bulk and offense.
Heracross - I don't think I really need to give justification for this one but I will regardless. It's my favorite pokemon without a shadow of a doubt and the pokemon that many of you know to associate with me above any other. The first time I ever used one I was blown away by its sheer power, and it has performed above and beyond its own weight every time I've put it on an in game team since. It has a solid position near the top of the usage stats in UU, which is a very good place to be power wise. Honestly I think the moment this guy isn't on my list is the moment it stops being my list.
Tyranitar - I like dinosaurs. No, I really like dinosaurs. I also like pseudo legendaries. Ever since second gen there've been two pokemon I was obsessed with using, but never got to until much later. Heracross and Tyranitar. Even 4 generations later with a multitude of cool fossil pokemon (Archeops and Aurorus being my favorites of the bunch) Tyranitar still remains the king of the prehistorically designed pokemon for me. There was also this thing where my older brother was a big fan of Dragonite, so when there were only two generations it was like Dragonite was his pseudo while Tyranitar was mine. That's never really left me.
A few other neat things about this team is that every type that is included is only represented once, there is a split between three slow bulky attackers and three faster frailer attackers, and a split between three special attackers and three physical attackers. All of those things are coincidences that arise from me taking my six favorite pokemon and slapping them all on the same team.