ChainofSecrets.org has been a core infrastructure provider since the very start of the network, providing public APIs for applications to use and several testnets + tooling.
Secretnodes is a Genesis Secret Network validator and the development organization behind the SecretNodes block explorer. SecretNodes runs API nodes for various application and is a core code contributor to various parts of the network including their own library called SecretDAO, a toolset for DAO creation.
Cashmaney AKA Itzik is a SCRT labs developer and the creator of Cashmaps. He runs nodes for the Keplr API cluster and several other applications.
Figment used to run the Datahub Secret API service where applications could buy query node services for their applications. Figment is a partner in the ecosystem fund and is also 1 of the 5 Ethereum bridge multisig participants.
🛹 Stake or Die! and their founder Sandy have been developers and infrastructure providers for a long time. Besides being active with the Testnet and the public API structure the team also helps the Secret foundation with website development.