Thanks for link, very useful.
Ethereum is the most popular because it was the first platform with smart contracts and easy way of making tokens, so they have advantage of the first mover, but other projects are developing fast. The second most popular ICO platfom is NEO, and they already have nice token ecosystem with very interesting projects, working decentralized exchange (Switcheo) and stable coin on the way (Alchemint). Waves is around for some time, but it's not so hyped and TBH I don't know much about their tokens. Besides the 5 mentioned in the link above, there are also Stellar, Ardor and ETC (probably a few more) which can be used for ICOs.