how to make icons and buttons bigger in ionic 2

Even for Icon we can use large and small to the ion-icon tag. This is how I had used

<ion-icon name="arrow-forward" item-end small></ion-icon>

In my Ionic 4 apps I adopted the following approach. In the *.scss file:

ion-icon { zoom: 1.5 }

Of course, zoom value depend on your needs.
Hope this help someone. o/

Icons

ion-icons are font icons so they can be edited the following Sass/CSS as they are essentially text:

    ion-icon {
        font-size: 20px; //Preferred size here
    }

Buttons

As for the button ionic has some inbuilt classes to affect size. For example:

   <button ion-button large>Large</button>

   <button ion-button>Default</button>

   <button ion-button small>Small</button>

You can also update the default Sass variable of $button-round-padding in your src/theme/variables.scss file, to the size that you would like. More on buttons can be found here

You can add this following code :

ion-icon {font-size: 3rem;}