These links are sites for free fonts for commercial use, which means that they may be use by an Independent Author for a commercial book. These fonts represent lists of good font sites, some with absolutely HUGE collections of free fonts.
*** Please note that GPL license free fonts are a writers bane. Any work they are incorporated into must be free of charge due to said font use, according to the GPL license itself. Avoid them like the plague.
I will add more as time permits.