Any kitchen sink type of workout would work. Kitchen sink is just referring to everything and all zones. Think about how group rides are typically ridden. Rarely is the power consistent so that is the type of workout you are looking to do.
If there are segments around where you live you can hit those full gas. These can range from short sprints to longer 10 - 20 minute efforts. Map out a ride that would include a few of these different duration segments and when you get to them go full gas. A short 1 minute segment would be an anaerobic effort while a longer 15 - 20 minute effort you might just do sweet spot.
Another thing you could do is a workout such as this. Warm up in zone 2. Then complete 2 x 15 minute Sweet Spot Burts efforts. During the 15 minute efforts do a Zone 5 effort every 3 minutes for 20 - 30 seconds. Like taking a pull in a hard fast pace line. Rest 7.5 minutes between. Ride 15 minutes. Then finish off with 3 x 2 minute full gas efforts. Rest 2 minutes between.
Honesty there could be about 100 different workouts you can do and variations. A coach could give you the specific type of workouts or ideas for each weekend. Like Frank said these group rides are about variety and pushing yourself. Also the idea of group rides is to think less about a timer and kind of go with the flow. Keeps the training a bit more fresh. Obviously group rides are not always a possibility and that is when a little creativity can go a long way.