I need daily ohlcvi data of all futures

[gr84xMaster]

Hello, traders.

I'm developing a trading strategy using ml. For training and backtesting, I need historical ohlcvi data of all future contracts.(from all(amap) exchanges. cme, ice, nse..) I think daily data is enough.

Could someone tell me where is the best place for get data? (correct, low price, small size..)

Thanks.