The question is a bit too open, unfortunately, but there are some general recommendations.
The first is to come up with some preferences. Are there BA you're particularly fond of? If so, pick'em, and build your force around them. Like the Longinus? Go Marik. Want to Salamander? Go Clan.
The second is to consider transport. I'm never happy deploying BA or infantry and not having a ride, even if (for example, in a defensive position) you might not put the vehicles on the board. For the Clans, that mainly means Omnis. So if you want a Trinary of BA, you more or less need a trinary of Omnis to carry them. There are some good Clan vehicle transports - the Svantovit & Eldingar are good speedy transports, and the wheeled Anat is ... well, cheap

Not all Clans are good at mix & match, but by 3100 there's more openness to mixed forces.
For Inner Sphere BA, you have Omnis - but you also have mag clamps. These little beauties mean any 'Mech or vehicle can carry a squad of mag-clamped BA. Which means cheap heavy APCs and other vanilla carriers with a 4-ton bay can now carry two squads, one in & one out. Then, there are omni vehicles as well, and some have bays as well. I'm particularly fond of the Manteuffel C - not only is the DA mini a good size for use on BT hexboards, if you lean that way, it's got an 8-ton bay - which means
two squads inside and one out, each.The armament - two LLPCs and an LRM-10 - are ideally suited to supporting BA, and the armour means you'll get there (eventually), having contributed along the way.
The main mag-clamp BA I can think of are the Capellan Fa Shih, the Marik Longinus variant, and the Feddie Infiltrator II variant. They''re usually a little anaemic compared to the base versions, which is why you put the meatier BA inside the bay and then add the extra squad clinging to the outside.
The last thing to think of is aerial assault - BA with jump-jets can be dumped like advertising leaflets from a VTOL, or troop-carrier like a Karnov. This does enable some fun tactics, although keep those birds moving until they drop their valuable eggs.
Any of that useful to you?