Advice and networks from experts (product, strategy, dev, UI / design, monetization, financial, accounting, legal, corporate structure, board of directors/advisors, bookkeeping, partnership leads, sales leads, hiring, angel / VC fundraising, access to experts across your industry / vertical / space, etc.)
Fellow founders as its own network (learn from and share experiences with other founders running their own startups in the incubator and the alumni across the years -- past and future)
Fundraising (one of the ultimate goals is to obtain funding to continue your startup, if your decision is to raise money in the first place -- typically, there is an Investor Day or some series of meetings toward the end of the bootcamp where you can meet with potential investors)