It really depends on what hospitals you go to and what their favorites are (and what their formulary offers). Just like fixation options in surgery, meds are really dealer's choice, and there are usually multiple ways to skin the cat (yet each place thinks their way is the best, so give the answer they will want if you have rotated there and know their preferences).
Below is a list of some of the more common ones I've seen used. It'd probably be a good idea to be familiar with them and their use/coverage for rounds/academics/interviews (esp bold ones which you will see used almost anywhere in pod surg service). I usually memorize generic names since that's what's more commonly used on boards exams and listed in journals, but you need to know brand names too (since that's usually how they're referred to by the attendings). Dosages are up to you... if your brain works that way (rote memory), you can go for it. If not, maybe try for at least some of the real commonly used ones in bold. In reality, you will (or at least "should") always double check in your book whenever you write Rx orders, even if you're 95% sure you know the dosage. Since you'll be looking them up anyways, I think there are better things to use your time on than memorizing dosages of 100+ meds, but JMO...
*disclaimer: I'd doing this mostly off the top of my head and my spelling sucks on non-English words, so go look em up to verify before you write a Rx order (or risk looking like an idiot when nurses/pharmacy/other docs read your order for amupcyllen/selbactum)
Clinic Rx:
-Pain/inflammation: Tylenol #3 and #4, hydrocodone (Vic, Lortab), Norco (hydrocodone also, but note it has less acet than Lortab or Vic), oxycodone (most won't use this, some do), Mepergan Fortis (ditto), propoxephene, methylprednisone, tylenol, indomethacin, tramadol, NSAIDs totally depending on preferences...celecoxib, ibuprofen, diclofenac, naproxen, etc
-PO Abx: cephalexin, amox/clav, clinda, tmp/smx, cipro, metronidazole, cefuroxime, levofloxicin, terbinafine
-Topical Abx: bacitracin, mupirocen, gentamycin, silver sulfa, triamcinolone, hydrocortizone, Lotrisone, miconazole, naftifine, etc
-Injected: lido, bupi, steroids are clinic pref (dex, triamcinolone, etc)
In ER/ inpatients /peri-op:
(all of the ones mentioned above... IV/PO ones like clinda, tmp/smx, etc are usually given IV if the pt has a line in)
-Abx: vanco, linezolid, amp/sulbactam, pip/tazo, cephazolin, ceftazidime, ceftriaxone, cefepime, imipenem
-IV/IM pain meds: morphine, meperidine (great med but not available everywhere), hydromorphone, ketorolac, fentanyl
-Anticoag: heparin, ASA, enoxaparin, warfarin
-Misc: etomidate, propofol, midazolam, diazepam, orphenadrine, meclopramide, ondansteron, promethazine, omeprazole, zolpidem, colchicine