Paris-Lyon. Split into two (quite distinct) trainsheds, linked by the ticket hall, previously referred to as 'plates-formes', rather confusingly to English speakers, now as 'Halls'. Hall 1 has platforms A-N, missing B and F. Hall 2 has platforms 5-23, odd numbers only (you can probably figure out what's happened here with the odd/even thing). Platforms 1-4 are reserved for the RER, down in the bowels.
A similar pattern is seen in the warren-like Chicago Union station. It's basically two opposing termini facing each other, with northbound trains using odd-numbered platforms, and southbound trains using even-numbered platforms, and a whole load of gubbins inbetween.
Copenhagen H has platform 1-12 and then platform 26. Yes, platform 26. Why? Well, it's a bonus platform, outside of the main train shed, formed of a track branched off of platform 6. To reach it, you have to walk down platform 6 (or any others), up to the road bridge, cross the road, then head back down the the platform. It was created to be a peak-hour terminating platform to ease congestion - it's more recently been used for Sweden-bound X2000 services after Sweden reinstated immigration controls. Why 26? Because it's supplementary to 6, and the 2- is the next increment from the highest numbered platform. This pattern is used elsewhere in Denmark - the forlorn platform 12 at Østerport, for example.