Hi Rasshme.

I haven't seen a slider fieldtype for Umbraco Forms, but it doesn't sound like it would be very difficult for you to build your own fieldtype.

Docs: Adding a custom field type: https://our.umbraco.org/documentation/products/umbracoforms/developer/extending/adding-a-fieldtype

You'd probably start with something like:

using System;
using Umbraco.Forms.Core;

namespace MyFieldTypes
{
    public class Slider : Umbraco.Forms.Core.FieldType
    {
        public Slider()
        {
            //Provider
            this.Id = new Guid("D6A2C406-CF89-11DE-B075-55B055D89593");
            this.Name = "Slider";
            this.Description = "Renders a slider input";
            this.Icon = "icon-navigation-horizontal";
            this.DataType = FieldDataType.Integer;
            this.SortOrder = 10;
        }
    }
}

Then in /App_Plugins/UmbracoForms/Backoffice/Common/FieldTypes/ add a html file called "slider.html" and use this HTML to start with:

<input type="number" tabindex="-1" class="input-block-level" style="max-width: 400px" />

Then for the rendering part you need to add a view in the /Views/Partials/Forms/FieldTypes called FieldType.Slider.cshtml. Start with this html:

@model Umbraco.Forms.Mvc.Models.FieldViewModel
<input type="number" name="@Model.Name" id="@Model.Id" class="text" value="@Model.Value" maxlength="500"/>

This should give you this output:

You've now created your own Forms FieldType! Now you can include some CSS and probably a JS framework to render a pretty Slider. You might also need som max/min settings which you can add to your Slider.cs file.

But this should give you a good start.

Remember if it turns out great and could be useful to others, package it up and share with others here on our!

Have a great day!