Are there any cards in the current standard format that have an attack that prevents the active Pokemon from retreating? Pokemon that are basics and are grass type would be most helpful.
There is only one that is a Grass Basic and has an attack that prevents the opponent from retreating:
Trevenant-EX (
XY: Primal Clash 19/160, 145/160). Below is a list of cards that have an attack. Entries in
bold text are either Basics or Grass Types.
Ariados (XY: Ancient Origins 6/98)
Aromatisse (XY: BREAKthrough 106/162)
Blaziken (XY: Furious Fists 14/111)
Flygon (XY: Primal Clash 110/160)
Gabite (XY: BREAKPoint 69/122)
Galvantula (XY: Phantom Forces 27/119)
Haunter (XY: BREAKThrough 59/162; Generations 34/83)
Jynx (XY: Furious Fists 37/111; Generations 36/83)
Klefki (XY: Furious Fists 73/111)
Krokorok (XY: Flashfire 57/106)
Mr. Mime (Primal Clash 101/160)
Octillery (XY: BREAKthrough 33/160)
Pidgeot (XY: Flashfire 77/106)
Poliwag (XY: Furious Fists 15/111)
Sandshrew (XY: BREAKthrough 75/162)
Scolipede (XY 53/146)
Scrafty (XY: Flashfire 59/108)
Seismitoad (XY: BREAKpoint 35/122)
Swellow (XY: Roaring Skies 71/108)
Tentacruel (XY: Primal Clash 72/160)
Zoroark (XY 73/146)
Not sure if you were excluding them for a reason, but if Abilities are allowed, then Dragalge (XY: Flashfire 71/106; XY; Black Star Promos XY10) can stop something from retreating if that Pokémon is Poisoned, via the Ability on Dragalge.