Sure, you can add another booster packet or some LME, liquid malts extract. MB sells those in Pale, Smooth, and Golden. You can read the descriptions on the online store.
Two booster packs will raise the ABV about 1%, without changing the taste of the beer. I think one pack of MB LME is about .55 lbs and also adds about 1% ABV but can change the flavor of the beer.
Look thru the recipes and you'll see a lot of them will show either using a bag or two of booster, or a pack of LME, to provide a little kick from what the standard can or craft refill would have. Those standard small cans of HME, are pretty weak in ABV by themselves and need some booster or LME to kick them into gear IMO.
i would look at one of the craft refills, like Northwest Pale Ale, or Long Play IPA. Those are good ones. By the way, partial mash recipes are very simple. if you can make tea by steeping a tea bag in hot water, you can do a PM. Adds flavor, body, maybe ABV....etc.
What is your goal? Not to sound mean, but if you want high alcohol drink scotch or vodka. Craft brewing is more about creating beers that have great flavor (subjective, of course). Often these beers are of a particular style (such as Oktoberfest, for example). Some have more alcohol, some less. You can boost alcohol, as mentioned by adding fermentable sugars. But, it reaches a point for the home brewer where the yeast are done (I would say 8% or so). Wines top out at 16-18% and they can be very dry. Your choice of yeast is important too; some attenuate the sugars more than others, besides adding to the flavor profile. Anyway, welcome to the forum.
With my Stout in the bottles and Oktoberfest in the LBK my thoughts turn to my next brew. I was thinking about an IPA. What IPA recipes from Mr Beer do you all recommend? I'm not sure that I'm quite ready to take on a partial mash. For reference I am fond of Founders All Day IPA and Goose Island.
Thanks in advance for your recommendations.