Quality maps
Try to think about maps that are both fun and expertly designed, and perhaps aren't frequently mentioned (cough cough airlock). I'll start:
1. Bitwise Orrery by Qui -- This is one of the best HTF maps I've come across. It's both visually and mechanically unique, with two separate channels, each with varying pros/cons. The defenses are simple and effective, and 3 flags is perfect for this map size. The original parameter of score-to-60 is solid IMO. This map also plays well with bots and low numbers.
2. Black Hole Speed by Unknown -- Classic CTF map, arguably Unknown's hallmark. Players may either zip around the sides of the map or through the middle. Each base is heavily armed, but the quick speedways allow for pounding offense. A single laserbeam at the output of the speedways is critical for defense. This is in my mind a very tactical map. Flag holders may remain at their own base for the protection and quick getaways, a tactic that is clever but very predictable. Alternatively, they may venture into the middle to hide, but risk vulnerability if found. All in all a fun and quality map, perfect for 2v2 or 3v3.
3. Twisting Halls by Rick -- This is a zone control map featuring only 4 zones! However, each zone is burrowed deep inside tunnels littered with walls, turrets, and laserbeams. While the tunnels are not particularly tricky to access, escaping unharmed is the real challenge. Due to the length of the tunnel, opponents alerted to a zone capture often have enough time to reach the entrance of the tunnel before the flag holder has escaped. This combined with plenty of external passageways requires expert sneakiness and explosive movement. Very fun map, but really needs at least 4v4 or 5v5 to be fun.