You can do the traditional standing calf raise machine or use a Smith machine. The goal here is to chase some progressive overload, so make sure you're tracking your sets, reps, and loading each week.
Also use an intensity technique called rest/pause. If you've never done rest/pause then get ready for some pain and gains.
After your warm-up sets, do an all-out set with a weight that causes you to fail at around 12-15 reps. Rest 20 seconds and go back at it for maximum reps. Rest 20 seconds and repeat that process one more time.
It's potentially the best hamstring exercise known to man, but it may also be the most difficult and the most humbling. Luckily, even doing it half-assed is hugely effective.