Container

display: flex or inline-flex.
flex-direction: row, row-reverse, column, or column-reverse. This determines whether items are ordered horizontally (rows) or vertically (columns).
flex-wrap: nowrap, wrap, wrap-reverse. By default all flex items will try to squeeze onto a single row.
flex-flow: Shorthand for flex-direction and flex-wrap.
justify-content: flex-start, flex-end, center, space-between, space-around. Determines how extra free space beyond that consumed by the flex items will be placed.
align-items: flex-start, flex-end, center, stretch, baseline. Defines how items are laid out along the cross axis of current row.
align-content: flex-start, flex-end, center, stretch, space-between, space-around. Determines how extra free space is distributed on the cross-axis.

Items (childen of container)

order: on an individual item allows for an integer to be given that determines the order of the item. By default they are ordered as they are delineated in the source code.
flex-grow: takes an integer. This defines how much of the space the item is allowed to consume in a given container.
flex-shrink: takes an integer.
flex-basis: length or keyword. The main-size keyword is deprecated, auto is an option, and there are content (max-content, etc.) available but not supported enough for usage.
flex: Shorthand for flex-grow, flex-shrink, and flex-basis.¹
align-self: auto, flex-start, flex-end, center, baseline, stretch. Overrides the default alignment or align-items specification for individual item.