This is a really hard situation for many a couple - the list of loved ones, family, friends, and much more has been compiled and who knew you had that many contacts! With guidelines given that up to 30 people can attend a wedding, this can seriously require a major change to your list, I don't think I've ever attended a wedding that small except the weddings I shot in lockdown with less than 15 guests! What I realised though is you may want to invite everyone and their horse, however small weddings can be beautiful too.
Some tips, to help you go through your list and reduce the numbers are:
1. Let people know that your wedding will be small, so people who don't receive an invitation are not surprised.
2. Are plus ones essential? You could implement a "no ring, no bring" approach.
3. Have a rule for how far you will go in extended family members - and stick to it.
4. How often do you see them? If it's less than regularly, then they may not make the list!
5. Finally - remember this is a wedding and day for you and your loved one.
Too often we feel obliged to invite countless people for fear of hurting their feelings, but you can record your wedding for those that didn't make the list to join you, whilst keeping those closest to you on the list, and making it the most enjoyable day.