Sympathies! Are you sure it's HR as a whole you are fed up with or just your current company/sector/industry? I've tended to move jobs within HR every 3-5 years and I find that massively helps keeps things fresh and interesting.
If you are stuck on the treadmill of constant ER work but you don't want to completely retrain/stay on a good wage, your easiest move would be within the profession, have you considered L&D, talent management, OD, reward, workforce analysis, even something like staff engagement, equality and diversity, health and wellbeing, outreach, coaching? If you look at large organisations they will often have specialist roles in these areas that don't have to do any of the boring ER stuff, and if you have been doing a single handed/generalist HR job you should be able to demonstrate the transferable skills, esp if you were prepared to take a small paycut in order to move into a specialist role (with a view to then being promoted back up to previous level within 1-2 years), or to self-fund some qualifications. Or if you work in a larger department can you look to move internally or at least do some work within a different part of HR, maybe even see if they'll fund some training for you to build your CV?
Or if you really do want entirely out, but don't really know what you want, I guess it depends on whether you need to maintain a certain income level or are prepared to totally lose income/need to shell out for qualifications for a few years? If the latter then that's a really big undertaking/investment so you need to be sure it's what you want long-term, you presumably can't afford to do it twice so you need to pick the right area, perhaps some life/career coaching would help identify this? If the former you could look at areas which have some crossover to HR like project management, business/office management, communications? Again you might need to self-fund some qualifications or be prepared to take a slightly lower level role at first?
Good luck!