Raiden of Ethereum = Lightning Network of Bitcoin
plasma = Ledger and Compute scaling solution of Blockchain
Sharding = Nodes are assgment as Collators (Collators gather 1. mini-description of transaction and 2. current state of the shard, that's called Collation. Collation is sended to super-node, which processes the transactions within those collations and maintain the full-description/state data of all shards)
Casper = POS + solve problems: 1. nothing at stake, 2. block time, 3. finality