Here are some practical examples of photos shot throughout the Sony a6400's ISO range from ISO 100 through ISO 102400.
Sony Alpha a6400 Mirrorless Camera with 16-50mm Lens — Glazer's Camera
Sony A6400 came! Tips you wish you knew when you first started photography? : r/SonyAlpha
The Sony a6400 is a Low-Light Beast on a Budget
Sony Alpha a6400 Mirrorless Camera with 18-135mm Lens — Glazer's Camera
Sony A6400 vs A6700 - A Detailed Comparison - Alpha Shooters
Sony A6400 Review
Sony A6400 with 16-50mm Lens Review
Sony A6400 review
Sony a6400 Review
Sony a6400 Mirrorless Camera (ILCE-6400/B) + Sigma 24-70mm f/2.8 Lens (578965) + Filter Kit + Bag + 64GB Card + NPF-W50 Battery + Card Reader + Corel Photo Software + Flex Tripod + More (Renewed) : Electronics
Sony a6400 High ISO Sample Images Test & Review
Sony Alpha A6400 Review