i read there are tools who speed up transactions, is it true? do they work with small fees also?
Those are mostly websites. They are owned by mining pools which can choose the transactions to include. By submitting a transaction to them, they can prioritise your transaction and it can potentially get it included in a block at a faster rate. A free one is ViaBTC's transaction accelerator and there's also BTC.com which is paid.
It depends on how small your fees are. I doubt ViaBTC would have their tool out for a long time, it doesn't benefit them.
are they free tools? and please share some links to those tools who work best?
ViaBTC (Free):
https://www.viabtc.com/tools/txaccelerator/ ---> Submit at the start of every hour.
BTC.com (Paid):https://pushtx.btc.com/