Is trapinch the only pokemon that can learn dig?

Answer 1

No, Trapinch is not the only Pokemon who can learn Dig. There are many species of Pokemon that can learn Dig, either by leveling up or by the TM.

These Pokemon can learn Dig by leveling up:

Sandshrew, Sandslash, Diglett, Dugtrio, Onix, Dunsparce, Steelix, Nincada, Trapinch, Gible, Gabite, Garchomp, Hippopotas, Hippowdon, Drilbur, Excadrill, Sandile, Krokorok, Krookodile, Durant, Bunnelby, Diggersby, and Zygarde.

These Pokemon can learn Dig by TM:

Charmander, Charmeleon, Charizard, Squirtle, Wartortle, Blastoise, Rattata, Raticate, Ekans, Arbok, Pikachu, Raichu, Sandshrew, Sandslash, Nidoran, Nidorina, Nidoqueen, Nidoran, Nidorino, Nidoking, Clefairy, Clefable, Vulpix, Ninetales, Jigglypuff, Wigglytuff, Paras, Parasect, Diglett, Dugtrio, Meowth, Persian, Psyduck, Golduck, Mankey, Primeape, Growlithe, Arcanine, Poliwag, Poliwhirl, Poliwrath, Kadabra, Alakazam, Machop, Machoke, Machamp, Geodude, Graveler, Golem, Slowpoke, Slowbro, Grimer, Muk, Onix, Krabby, Kingler, Cubone, Marowak, Lickitung, Rhyhorn, Rhydon, Kangaskhan, Pinsir, Eevee, Vaporeon, Jolteon, Flareon, Kabuto, Kabutops, Mew, Cyndaquil, Quilava, Typhlosion, Totodile, Croconaw, Feraligatr, Sentret, Furret, Ledyba, Ledian, Spinarak, Ariados, Cleffa, Igglybuff, Marill, Azuarill, Sudowoodo, Politoed, Aipom, Wooper, Quagsire, Espeon, Umbreon, Slowking, Pineco, Forretress, Dunsparce, Gligar, Steelix, Snubbull, Granbull, Shuckle, Heracross, Sneasel, Teddiursa, Ursaring, Swinub, Pilowswine, Corsola, Hitmontop, Raikou, Entei, Suicune, Larvitar, Pupitar, Tyranitar, Treecko, Grovyle, Sceptile, Torchic, Combusken, Blaziken, Mudkip, Marshtomp, Swampert, Poochyena, Mightyena, Zigzagoon, Linoon, Seedot, Nuzleaf, Shiftry, Nincada, Ninjask, Shedinja, Makuhita, Hariyama, Skitty, Delcatty, Sableye, Aron, Lairon, Aggron, Numel, Camerupt, Spinda, Trapinch, Vibrava, Flygon, Zangoose, Seviper, Corphish, Crawdaunt, Baltoy, Claydol, Anorith, Armaldo, Kecleon, Regirock, Groudon, Chimchar, Monferno, Infernape, Piplup, Prinplup, Empoleon, Bidoof, Bibarel, Cranidos, Rampardos, Shieldon, Bastiodon, Wormadam, Pachirisu, Buizel, Floatzel, Gastrodon, Ambipom, Buneary, Lopunny, Glameow, Purugly, Stunky, Skuntank, Bonsly, Gible, Gabite, Garchomp, Riolu, Lucario, Hippopotas, Hippowdon, Skorupi, Drapion, Croagunk, Toxicroak, Lickilicky, Rhyperior, Electivire, Leafeon, Glaceon, Gliscor, Mamoswine, Heatran, Oshawott, Dewott, Samurott, Patrat, Watchog, Lillipup, Herdier, Stoutland, Pansage, Simisage, Pansear, Simisear, Panpour, Simipour, Drilbur, Excadrill, Audino, Timburr, Gurdurr, Conkeldurr, Seismitoad, Throh, Sawk, Scolipede, Sandile, Krokorok, Krookodile, Darumaka, Darmanitan, Dwebble, Crustle, Scraggy, Scrafty, Tirtouga, Carracosta, Archen, Archeops, Zorua, Zoroark, Minccino, Cinccino, Axew, Fraxure, Haxorus, Cubchoo, Beartic, Stunfisk, Mienfoo, Mienshao, Druddigon, Pawniard, Bisharp, Heatmor, Durant, Landorus, Chespin, Quilladin, Chesnaught, Froakie, Frogadier, Greninja, Bunnelby, Diggersby, Litleo, Pyroar, Skiddo, Gogoat, Pancham, Pangoro, Furfrou, Meowstic, Binacle, Barbaracle, Helioptile, Heliolisk, Tyrunt, Tyrantrum, Sylveon, Hawlucha, Dedenne, Phantump, Trevenant, and Zygarde.