COSMOS ($ATOM), PoS ecosystem was launched in 2017 (Genesis Block March 13th, 2019)
Gas Token : $ATOM from US$0.03 to US$0.30 depends on the transaction (other ecosystem based on Cosmos technology BSC ($BNB), Terra ($LUNA), Crypto.com ($CRO), Fetch AI, Oasis, ... )
Wallets* : Cosmostation, Keplr (Chrome extension and Smartphone), Ledger
Bridge : Emeris (cross-chain interaction with Cosmos ecosystem), Terra Bridge (between Terra ($LUNA) and Osmosis), and withdraw on Cosmos ecosystem with Binance
Blockchain explorer : Atomscan, Mintscan
Launchpad : Cosmostarter (TBA)
Airdrop alert (*for stakers who delegate token) : Atom Tree Value
More information and protocols about COSMOS ecosystem : Cosmos Network, Map of Zones
NB: This is non-exhaustive overview of the ecosystem and subject to change, it's my point of view and not investment advise.
Other ecosystem : Terra ($LUNA), Elrond ($EGLD), BNB Chain (ex-BSC) ($BNB), Cardano ($ADA), Optimism, Arbitrum
Referral bonus (earn 10€, when start with 100 €) : Another way to stake in one centralized platform for beginners is to manage your token with Feel-Mining