Most online sportsbooks only offer teasers within these markets. Football and basketball, both collegiate and professional, synergize particularly well with teasers.
Teaser bets derive from point spreads and totals, as those are the only bet types where bettors can buy points.
Value opportunities do exist at online sportsbooks, but finding them takes patience and precision. Teasers were once exploitable, but sportsbooks have taken preventative measures against this behavior. The format has evolved significantly throughout the years, and not necessarily for the better. Teasers win far more often than equivalent parlays, which accounts for their reduced payouts.