Honestly, you can do about anything with Smolicons but there are some small details that you should know.
Reselling and redistribution
The MIT license allows you to use Smolicons in any way you want as long as you abide by its stipulations.
You're definitely more than welcome to accredit the resource in your work!
Logos and brand icons
The brand logos and icons used in the project are trademarks owned by the respective entities. The use of these trademarks does not indicate endorsement of the trademark holder by Smolicons, and by extension Omelette Creative, nor vice versa.
Please do not use brand logos for any purpose except to represent the company, product, or service to which they refer. I highly recommend you stick to their respective brand guidelines.
The MIT License (MIT)
Copyright (c) 2021 Smolicons
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.