In 2021 this Sunday occurs during Creation Time and suggestions for songs which can be used to complement or substitute for the lectionary based material can be found here. You can find a YouTube playlist here with many of the songs suggested below.
The Epistle calls on us to praise the name of Jesus and this could suggest opening hymns such as At the name of Jesus (CH 458 / MP 41), All hail the power of jesus’ name (CH 457 / MP 13) or worship songs like My Jesus, my Saviour / Shout to the Lord (CH 531 / MP 1003 / CCLI) and Blessed be your name (MP 1036 / CCLI). Alternatively if you are focusing on the Gospel then you might want to pick up the theme of Jesus’ call to the children with Come, children, join and sing (CH 185), Here in this place / Gather us in (CH 623) or Let us build a house (CH 198).
Psalm 26 doesn’t have many settings but Stand with us, God (GIA) is a good option. The suggested tune by Vaughan Williams is possible but O waly waly would have a similar feel and is probably more widely known. An alternative could be Give judgement, Lord; consider my appeal (CCLI) which was written to be sung to Unde et memores but could also be sung to Song 1.
There aren’t many songs which link to the first part of the Gospel but Says Jesus, ‘Come and gather round’ (CH 342) is a great hymn by Leith Fisher to link to the part about children. Jesus loves me! this I know (CH 564) would be a well known hymn to consider while I am a child of God (MV 157) would offer a sense of committing to Jesus’ message to us.
Thanks to God whose word was spoken (CH 605) or Lord, you sometimes speak in wonders (CH 606) would link in to the opening of Hebrews while there are lots of classics that can link to the full passage including Meekness and majesty (CH 356 / MP 465) and The head that once was crowned with thorns (CH 438 / MP 647). Christ triumphant, ever reigning (CH 436 / MP 77) is a fabulous contemporary hymn often sung at Ascension but which could work here and is well worth introducing if your congregation don’t know it while Of the Father’s love begotten (CH 319) is most often sung at Christmas but also links well.
Songs about the book of Job has been a gap in hymnody so there are some interesting recent hymns to explore such as when When Job the great was brought to tears (GIA) sung to Third Mode Melody. You could also consider songs about God’s place in the difficult times of life such as Wait for the Lord (CH 276), My life flows on in endless song (How can I keep from singing) (CH 565) and Healer of our every ill (Hymnary) or about those who carry these burdens for us with Rejoice in God’s saints (CH 742).
If you have focused on the Old Testament and/or Psalm then you might want to consider songs about our need to trust God in times of trouble and which praise God for being there in those times. Classic hymns on this theme are A safe stronghold our God is still (CH 454 / MP 2) and All my hope on God is founded (CH 192 / MP 16) while There's nothing that our God can't do (CCLI) and My lighthouse (CCLI) are more recent options.
Otherwise you could consider At the name of Jesus (CH 458 / MP 41) or All hail the power of jesus’ name (CH 457 / MP 13) if you haven’t used them as an opening song or How shall I sing that majesty (CH 128) which also picks up the themes from the Epistle. Some general songs such as In Christ alone (MP 1072 / CCLI / Getty) or Yet not I but through Christ in me (CCLI) could also work.