The best replacement for ttf is otf.

The best alternatives to ttf are rated as following:
★★★★★  otf
★★  ttc
★★  otf mac
★★  postscript
★★  opentype
★  otf fonts
★  cff
★  woff
★  eot
  shx
  bitmap font
  pfm
  .otf

Your alternative for ttf is not listed? Suggest!
Speaking about ttf, one probably shouldn't forget about gd.

Other search terms related to ttf and their ratings are:
★★★★★ gd
★ font face
You have in mind a companion for ttf and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of ttf in all years. Click on graph for more.
ttf
otf
ttc