Assembling a type collection is more than just filling holes in an album. There are the basic types to collect, such as Shield nickels, Mercury dimes, and so forth. But what to include in a type set? It would depend on how many years and how much you want to include.
More than any other kind of collecting, collecting by type can be tailored to the individual. Perhaps a 20th Century type set would satisfy you. Maybe after putting that set together, you may want to expand the set, to 19th Century issues. Or you might want to go deluxe and go all the way back to 1793. Your interests and cash outlay can help you decide.
Every single coin doesn't have to be Mint State. Older coins can show wear, excessive wear. Every type collector would be happy with a small eagle half dime or a Flowing Hair dollar. Should you include only the basic types, or include more subtle ones, such as Liberty Seated coins with drapery? Again, it's up to you.
Keep in mind that the set probably will never be complete, if you collect a deluxe set. The small eagle half dollar, and quarter too, are stoppers for almost everyone. The small eagle coins are tough, and so is the Chain cent. Maybe you'll be happy to see how far you can go.
Type collecting is worthwhile, educational, and can keep a collector busy for many years.