For NFL Teasers, FanDuel does provide some good ones but they are all non-traditional.
2 team 3 point teasers: +140, use them to cross 3 on juiced lines
3 point 4.5 point teasers: +200, use them to tease down juiced 7 point favorites or tease up juiced 3 point underdogs
2 team -6, -6.5, -7.5 teasers: +700, +750, +900, use them on huge favorites. Avoid cross key numbers (17, 21) if you can.