No matter which pack you purchase, each one has cards of different rarities
Oath is one of the best main-deck cards you could run to give you game against Shops
Personally, I see less than 10 real stinkers, with Tasigur, Lavaclaw, Wildwood, and Balefire being the real stand out failures, but the real question here is how much middling promos like Ulamog or Creeping Tar Pit will end up at, and how much the true maniacs like Liliana of the Veil will drag the mean upwards

Locations Red Blue Yellow Cerulean Cave Gold Silver Crystal Johto: Route 45 , Ice Path , Kanto: Route 15 , Celadon City , Rock Tunnel Ruby Sapphire Emerald Route 103 - Emerald , Route 104 , Route 109 , Route 115 , Route 123 - Emerald , Route 123 - Emerald , Lilycove City , Safari Zone - Emerald , Victory Road FireRed LeafGreen Route 13 , Route 17 , Celadon City , Cerulean Cave , Rocket Hideout , Silph Co , Three Island , Five Isle Meadow , Outcast Island Diamond Pearl Route 206 (With Dowsing Machine) , Route 213 , Route 216 (With Dowsing Machine) , Route 222 (With Dowsing Machine) , Jubilife City (Get 2 Numbers in the Lottery) , Eterna City (With Dowsing Machine) , Solaceon Town , Veilstone City , Valor Lakefront , Survival Area (With Dowsing Machine) , Stark Mountain Platinum Route 206 (With Dowsing Machine) , Route 213 , Route 216 , Route 216 (With Dowsing Machine) , Route 222 (With Dowsing Machine) , Jubilife City (Get 2 Numbers in the Lottery) , Eterna City (With Dowsing Machine) , Solaceon Town , Veilstone City (With Dowsing Machine) , Valor Lakefront , Survival Area (With Dowsing Machine) , Stark Mountain , Floaroma Meadow (With Dowsing Machine) HeartGold SoulSilver Johto: Route 39 (With Dowsing MCHN) , Violet City , Radio Tower (Goldenrod Lottery Prize - 2 Numbers Match) , Mt

While its name and grandmotherly attire might make for a good initial gag, it's the special effect that makes you chuckle