Best bang for buck is Shadow imo. Very challenging gameplay and good to have one like that in a collection. Fish Tales another challenging game that goes great with WH20. For more modern games, hard to beat a MET pro. Fantastic gameplay and relatively cheap. Last suggestion is getting a Lawlor pin for a mix of designers. His games are a lot of fun for all ages and skill levels. TZ, TAF, and DI are the best but many other great ones.