I was going to build a VGC team and started to wonder about pokemon types that are good to have. When I watched Justins tournament it looked like everyone had a wash rotom but now that its VGC 15 rules what type do you think will be used on competive teams?
Yeah. Good type cores are Fire/Water/Grass and Dragon/Steel/Fairy if you need somewhere to start. It's fine if they have secondary types too. For example, you could have a F/W/G core of Azumarill/Rotom-Heat/Amoonguss if you think those pokemon are good for your team.
Great Pokemon types for VGC are Fire, Steel, Dragon, Fairy and Normal types, they have very few weakness, great base stat totals and more diverse move pools.
Also I recommend checking out this page for more information on the usage stats in this year's VGC