Does anyone know of a list provider for users of cloud software

I am trying to get a list of users of a particular software to target for competitive displacement. I will give the exact name to the list vendors

yes this is widely available. the simplest will be Apollo (Cognism, Zoominfo...) because it's right in the filters.

there are also data sources you can access via api if you're using Clay. Here's my running collection of gtm engineering tools for pricing, links and details. • BuiltWith • Wappalyzer - Tech detection & lead gen tool • SimilarTech - Technographics for B2B lead gen • Webspotter - Tech stack detection + contact discovery • Bloomberry - Technographics & company intelligence • CRFT Lookup - Fast tech stack lookup (free) • Ful.io - Free site tech lookup • NerdyData - Code search engine for finding sites using specific scripts