Bloom Dragons are so boring (I am polite) to obtain I prefer to have at least 3 Level 100 and several Level 20 of each Type, just in case I get a new 4*/5*. Of course I keep also a lot of Manyus as well, and sometimes Ampys.
All of this added to the fact I keep (and upgrade) my 2*, that take a lot of space (sometimes 210 is not enough).