This will hopefully be a growing list of various HTML+CSS layouts, components and techniques. The goal is to have a handy resource whenever needed and avoid having to start from scratch all the time or search the web for a solution.
Layouts
Single column layout
Two column layout
Two column layout with header
Three column layout
Three column layout with header
Responsive sidebar layout
Headers & Hero Sections
Header with search bar, menu and profile dropdown menu
Full page header with logo, slogan and menu
Responsive hero section
Sticky header with scroll hide/show
Footers
Footer with links and newsletter form
Menus & Navigation
Simple responsive hamburger menu
Responsive multilevel pop-down menu
Responsive tabs
Tables & Grids
Responsive table
Responsive card grid
Forms
Simple newsletter form
Simple contact form
Modals, Popups & Notifications
Responsive modal/popup dialog
Responsive toast notification
Simple alert/message banner
Cards & Profiles
Galleries & Timelines
Responsive image gallery with lightbox
Timeline / vertical steps layout