Finviz is one of the best free websites for analyzing the stock market (mainly U.S.).

What is it used for? It is a financial analysis and visualization platform that helps you:
Search and filter stocks (Stock Screener):
You can filter thousands of stocks by technical criteria (RSI, moving averages, chart patterns), fundamental (P/E, EPS, dividends, debt, etc.) or descriptive (sector, market cap, etc.).
View heat maps (Heatmaps):
Visually shows which sectors or stocks are rising or falling (red = down, green = up).
Quick charts: Charts with technical indicators.
News: Summary of news by stock or the market.
Insider Trading: View insider buying and selling (very useful for what you were looking for earlier).
Portfolios: Create and track your own stock lists.
Others: Futures, forex, crypto, earnings (earnings), upgrades/downgrades, etc.
It’s very popular among day/swing traders and investors because it is fast, visual, and powerful even in its free version.