CoinGecko

CoinGecko is a data platform for cryptocurrency markets, tracking prices, trading volumes, market capitalization and other metrics across a range of digital assets and exchanges. It is used by traders, investors and researchers who want to compare coins, follow market movements over time or research the background of a specific project before deciding whether to act on it, without relying on any single exchange for pricing data.

Its ads.txt file lists 51 ad systems used for programmatic advertising. Ascendeum is named as a sales house involved in placing ad spots on the site.