"Supabase integration with Gmail" matching MCP connectors:

Abstraxn Agent Kit gives AI agents instant access to real-time Web3, blockchain, and market data with no signup or API key. Access blockchain tools, crypto, wallet, ENS, transaction simulation, and travel APIs through one MCP server, with paid calls settled directly from the user's crypto wallet via x402—without Abstraxn holding or custodizing funds.

Open AI Visibility Index for crypto and Web3. Weekly share-of-answer measurements for 24 tracked brands across ChatGPT, Perplexity and Gemini, from a frozen versioned prompt panel. Five read-only tools: full index, per-brand lookup, brand list, complete measurement history and methodology. No auth, no API key. Data is CC BY 4.0 with a permanent archive of every weekly snapshot, so any figure can be verified independently.

Free, keyless MCP server with 50 read-only blockchain tools for Bitcoin, Ethereum, and Mezo. No installation, no API key required -- just add the URL to your MCP client and start querying balances, transactions, blocks, ENS names, ERC-20 tokens, smart contracts, and more. Runs on Cloudflare's global edge network via Streamable HTTP. All tools are strictly read-only and stateless.

Free, keyless MCP server with 50 read-only blockchain tools for Bitcoin, Ethereum, and Mezo. No installation, no API key required -- just add the URL to your MCP client and start querying balances, transactions, blocks, ENS names, ERC-20 tokens, smart contracts, and more. Runs on Cloudflare's global edge network via Streamable HTTP. All tools are strictly read-only and stateless.

Live operational + integration registry for Bittensor subnets: APIs, schemas, health.

A colony of AI citizens: join with no credential, prove skills, earn, vote on the rules.

TRON blockchain MCP server powered by the GoTRON SDK — query accounts, balances, TRC20 tokens, blocks, transactions, and smart contracts; build and sign transactions for transfers, staking, voting, and contract calls. Supports mainnet, Nile, and Shasta testnets with Go-based tooling for energy estimation and transaction building. Available via stdio or hosted Streamable HTTP

Pay any Algorand x402 invoice with any asset, plus DEX swap quotes and unsigned builds.

Read-only XRP Ledger MCP tools with proof-annotation envelopes and signed daily snapshots.

Vealth work board: find real work, claim free with your wallet, prove it. Free onchain anchoring.

Nine chain onchain intelligence with a verifiable onchain signal attestation stream

Agent-native storage with cryptographic verification on Solana. Keyless: clients sign and pay.

On-demand unblocking for AI agents: find blockers free, pay via x402 on Base, get anchored proof.

Crypto price and threshold consensus with ML-DSA-65 attestation and Base anchoring.

Marketplace of pay-per-call APIs for AI agents. Top up once with USDC, then call any listed API - gasless, walletless, metered per request. Includes onboarded providers and hundreds of x402-native APIs discovered on-chain.

Production-ready TronSave MCP server focused on helping agents and clients buy and sell TRON resource quickly through one unified interface, with fast order execution, pricing/estimation tools, and secure session-based workflows.

Agent-to-agent dispute resolution and arbitration with on-chain settlement

Book a strategy call with Trust Boundary Systems (blockchain, stablecoins, MPC, ZK, AI advisory).

MCP server for AI agents to discover campaigns by humans and donate USDC directly on Base.

NCTR Alliance rewards — search bounties, check earning rates, and discover communities.