If you can get over the dated interface then MFUOnline is the best portal. It is the official portal of AMFI (Association of Mutual Funds in India) and once you set it up, you can invest in almost all mutual fund schemes available.
MF Utiility is an Initiative by and For the Mutual Funds in India and facilitates convenient submission of transactions for any of the participating mutual fund both online and offline
www.mfuindia.com
Here's the list of all available fund houses, except UNION, UTI, and YES. They are listed after TAURUS on the list.
View attachment 103031
Just don't go crazy investing in multiple mutual funds after you've created the account. There's no point in spreading yourself too thin.