List of OPC servers

So happened that starting from university and through my career I worked with Kepware OPC only. It really fitted any needs I had. But now, the company I'm working at met with a problem - we cannot order the mentioned Kepware OPC server. So while we investigating this, I need some solid alternative. Requirements are not so high at the moment: connection to Modbus data sources and storing into MS SQL, preferably via ODBC. But any additional capabilities are strongly welcomed.
I ended up googling for some OPC servers and have to say it was not the best my google experience. So can someone offer me a list of vendors to look into for Kepware remplacement, temporal or not.