Building an amazing website with bad niche looks like building 5 stars hotel on the moon, no on will visit your site if your niche was not demanded.
i will try to focus on best fields which you can choose your niche from.
The basic rule in searching for the best Niche for affiliate marketing is by looking for: ” What people are looking for? “.
So we can find this in most categories:
1- Make money: almost most people look for an additional income especially those without steady work, so your affiliate site can find big place in this field.
e.g. how to make money online, affiliate marketing, working from home,…etc
2- Save money: a growing numbers of people have financial problems because of many things, you can focus on one of these factors and make it your niche.
e.g. loans, insurance, debt…etc.
Lot of people having their problems with marriage,dating, finding soulmate…etc, so you can attract them by making a site which gives tips or by adding a platform for meeting with others or for sharing their problems.
As an affiliate you can offer them an ebooks or ask for subscription fee…etc.
there are hundreds of sub-niche you can create: e.g. how to attract women/men, make your ex back,best places for dating…etc.
Health and fitness:
People looks all time for medicines, prescriptions and tips which they want to imagine that it will heal them and make their physical or psychological condition better.
This includes many niche: Fitness, health, food…etc
And many hundreds of sub-niche: Fitness for fat people, health tips for pregnant, health drinks…etc.
Hobbies and activities:
People will spend money over and over when they find something which make them happy like doing their hobbies and favourite sports.
Many in this categories are rich people, and they will pay lot of money so i recommend to focus on expensive sports/activities like hunting, golf, fishing..etc
They will pay money for buying tools, equipments, guides which help them to become better with their favourite activities .
In the end there is no #1 niche as you can all the time make your niche #1 by:
1- Being creative when choosing your niche, it is better at choosing sub-niche than general topic, (See article: How to choose your Niche).
2- Giving an attractive and unique information about your niche to your website visitors.
3- Choosing high profitable products which match your niche.
4- Focus on few products and give your experience on them (you have to try them personally) and don´t clutter your efforts here and there.
5- Proper planning to increase your site traffic.