There are broadly 4 types of smallcases:
Thematic - smallcases centered around trending market themes (Eg: Rising Rural Demand)
Sector Trackers - smallcases that take sector-specific exposures (Eg: Insurance Tracker)
Model-based - smallcases centered around financial models (Eg: Dividend Aristocrats)
Smart Beta smallcases - Large cap focused strategies with an objective to beat the market