Datadog
OfficialDatadog publishes a JSON API of IP ranges per site for agents, API, APM, logs, synthetics, webhooks, and more. Each Datadog site (US1, EU1, US3, US5, AP1, AP2, Gov) has its own endpoint.
Datadog IP ranges — US1 (datadoghq.com)
Official feedCovers agents, API, APM, logs, synthetics, webhooks, and more for US1 — pick the site that matches your org.