"Examples of MCPs (Microservices Communication Protocols) That Do Not Require API Keys" matching MCP connectors:

Crevio's MCP server lets an agent run a real online business, not just read from one. It exposes a delegation surface (ask_crevio, start_task, wait_for_run, send_message, resolve_approvals) plus code_search and code_execute for calling the full Crevio REST API - products, customers, orders, email, socials, and sites.

Read-only Amazon SES observability: search events, inspect bounces, pull delivery stats.

Teaches AI to write HTML email that renders in Outlook, Gmail, and Apple Mail. 19 rules, 6 comps.

Coldrig — cold-email infra run by your agent: 28 MCP tools, live sending, free sandbox. $99/mo.

Email posture for any domain: can it receive mail, can it be spoofed? MX, SPF and DMARC.

7 outreach, sequencing, call-coaching and CRM-hygiene skill products. 6 of 8 free.

An AI agent that runs your online business: products, orders, customers, email, and sites.

Send e-cards to your human. The first store built for AI agents; free, no API key needed.

Gives an AI agent its own email address: create mailboxes, send and reply, read the inbox, and block until a reply arrives. Includes a draft lifecycle so a human can approve outbound mail before it sends.

Find and enrich leads, run multi-channel outreach, and manage the sales pipeline.

Keyless email checks: disposable, role, and free-provider detection, MX, and typo suggestions.

7 sales-outreach persona and skill products plus deliverability tooling over MCP: audit_copy scores email copy out of 100 for spam triggers and personalization, sequence_planner builds opt-out-respecting cadences, subject_line_scorer ranks up to 20 lines, utm_builder produces tracking URLs, and get_free_skill loads any product's complete free gateway skill.

Send transactional email, run campaigns, manage contacts and automations, audit deliverability.

AI invoice follow-up emails for freelancers. Draft-only, never sends for you.

Render markdown into email-safe HTML, lint drafts for deliverability problems, and preview emails.

Manage Subscribers, Broadcasts, Sequences, Automations, and reporting in Mailrith.

Verify email addresses and clean lists to improve deliverability and sender reputation.

Email OS for agents - real-inbox search, triage, commitments, and a verifiable BEC hard-stop.

Give an agent its own inbox: send, receive, and pull signup codes from real email.

Emailable MCP — wraps the Emailable email verification API (emailable.com)