Here are three main icon collectioins for web development, including Google material design, font awesome, and Bootstrap Glyphicon.
Website: https://material.io/icons/
A Usage Guide: http://zavoloklom.github.io/material-design-iconic-font/
Usage
1. Include the following line in the html header
<link rel="stylesheet" href="path/to/material-design-iconic-font/css/material-design-iconic-font.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>2. use an icon
<i class="material-icons">face</i>website: https://getbootstrap.com/docs/3.3/components/
Usage
1. Include Boostrap To call a Glyphicon, you will need to include the Bootstrap library and css in the header.
<link rel="stylesheet" href="https://unpkg.com/leaflet@1.2.0/dist/leaflet.css"/>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">2. use an icon
<span class="glyphicon glyphicon-search" aria-hidden="true"></span>Usage
website: http://fontawesome.io/
1. Include Font Awesome
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">2. use an icon
<i class="fa fa-bath" aria-hidden="true"></i>If you are interested in more about icons, please read https://www.w3schools.com/icons/default.asp.
website: http://map-icons.com/
Map Icons extends the Google Maps Marker Object to enable either an image or SVG marker to be used with the icon placed on top as a label.
Include the fonts in the dist/font directory as well as the dist/css/map-icons.css stylesheet to use icons in markup as an icon font.
To use the icons with Google Maps include dist/js/map-icons.js
Icon class names are to be used with the map-icon class prefix.