The worst thing you are likely to see in a small, competitive game is a VC army running Cairn Wraiths (ethereal) that can take advantage of all of the power dice raising models. But if there are lots of Skaven or DoC armies around, this is much less likely to happen.
For Lizardmen, the Diadem of Power, as already mentioned, is a great item on a Skink Priest in small games. I'd personally be tempted to skip the Saurus character in favor of greater numbers in your core units, but unless your Priest rolls a damaging spell(s), his magic weapon would be the only way to deal with ethereal outside of CR. The Chameleons are another great suggestion since they are likely to be able to deploy very advantageously and would be a huge headache in lower point games since the opponent will have to focus a good portion of their points to deal with them for a round or two. A Salamander if you can fit could work well as suggested too. Skrox units and Terradons are units that have never worked well for me consistently, but a lot of people seem to find them very effective.