type

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form>
 <input type="text" name="txt1" />
 <button type="button">Button</button>
 <button type="reset">Reset Button</button>
 <button type="submit">Submit Button</button>
</form>
</body>
</html>

image button

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form>
 <button type="button">
  <img src="https://www.w3schools.com/images/compatible_chrome.gif" />
 </button>
</form>
</body>
</html>

name, value

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form action="/formtest3.html" method="get">
 Choose your favorite subject:
 <button name="subject" type="submit" value="HTML">HTML</button>
 <button name="subject" type="submit" value="CSS">CSS</button>
</form>
</body>
</html>

disabled

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form>
 <button type="button" disabled>Button</button>
</form>
</body>
</html>

autofocus

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form>
 <button type="button" autofocus>Button</button>
</form>
</body>
</html>

formaction

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form action="/formtest3.html" method="get">
 <input type="text" name="txt1" /><br>
 <button type="submit">Submit</button><br>
 <button type="submit" formaction="/hrtest.html">Button</button>
</form>
</body>
</html>

formenctype

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form action="/formtest3.html" method="post" enctype="application/x-www-form-urlencoded">
 <input type="text" name="txt1" /><br>
 <button type="submit">Submit</button><br>
 <button type="submit" formenctype="text/plain">Button</button>
</form>
</body>
</html>

formnovalidate

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form action="/formtest3.html" method="get">
 <input type="email" name="txt1" /><br>
 <button type="submit">Submit</button><br>
 <button type="submit" formnovalidate>Button</button>
</form>
</body>
</html>

formtarget

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8"/>
  <title>test</title>
</head>
<body>
<form action="/formtest3.html" method="get" target="_blank">
 <input type="email" name="txt1" /><br>
 <button type="submit">Submit</button><br>
 <button type="submit" formtarget="_self">Button</button>
</form>
</body>
</html>