draw.io - Online diagramming application
Truebit - Truebit is a blockchain network that allows for trustless smart contracts.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
Polkadot - Polkadot is a Web3 decentralized cross-blockchain protocol that seeks to connect different blockchains, enabling them to share security, interoperate and transact with each other.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
Covalent - Interactive icebreakers for remote teams